Signal transmission and reception method, signal transmission and reception device

Abstract

To provide a signal transmission / reception method and a signal transmission / reception device that reduce unnecessary waves existing in a Nyquist band and optimize characteristics of desired waves when digitizing an analog input signal.SOLUTION: A signal transmission / reception device keeps the frequency band of an input signal within a sampling frequency band of an analog-to-digital conversion device, reduces unnecessary waves by keeping a total power within a reception range of the analog-to-digital conversion device, analyzes the frequency after digital conversion, adjusts a filtering band of a bandpass filter device based on an analysis result, and keeps the input signal within the adjusted filtering band. Unnecessary waves existing in a Nyquist band are reduced by the combination of the bandpass filter device and an equalizer to improve the characteristics of the desired waves. An amplitude control device optimally identifies the amplitude of unnecessary waves, makes it possible to receive a signal without deviating from the reception range of the analog-to-digital conversion device, and reduces unnecessary waves and improves the signal-to-noise ratio of the signal while reducing distorted signals.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The signal transmission / reception method and signal transmission / reception apparatus of the present invention can be used in various fields where analog signals are transmitted, such as various fields including television broadcasting, relay apparatuses and retransmission systems in CATV systems, mobile phone communications, and the like.

Background Art

[0002] In various transmission / reception systems such as television broadcasting, relay apparatuses and retransmission systems in CATV systems, and mobile phone communications, analog high-frequency signals of VHF band or higher are used for signal transmission. Analog high-frequency signals usually contain many unwanted waves. Due to the influence of the unwanted waves, the signal-to-noise ratio, distortion characteristics, etc. deteriorate, so it is necessary to suppress (reduce) the unwanted waves.

[0003] When the transmitted high-frequency signal contains multi-channel signals, since the bandwidth between channels is narrow in an analog input signal (hereinafter simply referred to as "input signal"), it is difficult to remove the unwanted waves mixed between channels. Also, when the amplitude and phase of the signal (desired wave) in the necessary band in the input signal are subject to fading such that they change according to the time axis due to the external environment, it is difficult to eliminate the influence of fading with an analog signal as it is. For this reason, in a signal reception apparatus that receives an analog high-frequency signal of VHF band or higher, it is common to convert the received input signal into a digital signal by an analog-to-digital conversion device (ADC), remove the unwanted waves, and then convert it into an analog signal by a digital-to-analog conversion device (DAC) for transmission (transmission).

[0004] When digitizing an analog signal, if the frequency bandwidth of the analog signal is wide, undesirable unwanted signals may be introduced into the bandwidth. If unwanted signals with a higher power level than the desired transmission signal, or fading that causes fluctuations in amplitude, phase, frequency, etc., are included, and their power exceeds the upper limit of the analog-to-digital converter's reception range, the converter will saturate and distortion will occur. If the power level of the entire bandwidth is lowered to prevent distortion, the power level of the desired signal will decrease. In this case, there is a problem that the signal-to-noise ratio of the desired signal deteriorates as it approaches the lower limit of the analog-to-digital converter's reception range. Furthermore, if the amplitude or phase of the desired signal in the input signal is affected by fading that changes over time due to external environmental factors, even if the received signal has a sufficient signal-to-noise ratio for demodulation, the demodulation function of the receiving device may not work, resulting in a failure to receive the signal.

[0005] Patent documents 1 to 4 describe digitalization devices that reduce unwanted signals. Patent document 4 discloses a method for receiving wireless signals that uses an automatic gain control (AGC) function to keep amplitude fluctuations constant. However, when receiving devices and relay devices are connected in multiple stages, or when fading is severe, there are problems such as the signal-to-noise ratio deteriorating due to momentary interruptions, stops, and recovery of the input signal, or adverse effects on surrounding channels. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6770083 [Patent Document 2] Japanese Patent Publication No. 2018-014718 [Patent Document 3] Japanese Patent Publication No. 2018-009971 [Patent Document 4] Patent No. 5583839 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem to be solved by the present invention is to provide a signal transmission and reception method and a signal transmission and reception device that can reduce (including reduction; the same applies hereinafter) noise contained in the analog input signal (unwanted waves originating from the input signal) and unwanted waves that occur when the received analog signal is converted into a digital signal with a sufficiently wide bandwidth relative to the desired wave (unwanted waves associated with digital conversion), and can also improve the signal-to-noise ratio of the desired wave that deteriorates depending on the reception range of the analog-to-digital conversion device. Hereinafter, unwanted waves originating from the input signal and unwanted waves that occur as a result of digital conversion will be collectively referred to as unwanted waves. Unwanted waves include spurious signals, noise, fading, steep amplitude fluctuations, overall amplitude fluctuations, phase fluctuations, frequency fluctuations, noise, other things that degrade the desired wave, and unwanted signals that extraneously enter the bandwidth taken into the AGC (the same applies hereinafter). [Means for solving the problem]

[0008] (Signal transmission and reception method of the present invention) The signal transmission and reception method of the present invention is a signal transmission and reception method that converts an analog input signal into a digital signal using an analog-to-digital converter, reduces unwanted signals mixed in the digital signal, and then converts it back into an analog signal using a digital-to-analog converter for output, and is characterized by its method for reducing unwanted signals.

[0009] [Method 1 for reducing unwanted signals] The method for reducing unwanted signals in the present invention involves first using a bandpass filter to bring an analog input signal within the conversion bandwidth of an analog-to-digital converter, then converting it into a digital signal using the analog-to-digital converter, analyzing the digital signal, and adjusting the passband of the bandpass filter based on the analysis results so that unwanted signals contained in the digital signal are reduced. The input signal is then input to the bandpass filter after the bandwidth adjustment so that unwanted signals are reduced.

[0010] [Method 2 for reducing unwanted signals] The unwanted wave reduction method in the present invention may also be a method in which the amplitude of an analog input signal is brought within the dynamic range of an analog-to-digital converter by an amplitude control device, and then converted into a digital signal by the analog-to-digital converter, the amplitude (power) of the digital signal, or the amplitude (power) of the analog signal after amplitude control by the amplitude control device but before digital conversion, is analyzed, and based on the analysis results, the amplitude range of the amplitude control device is adjusted so that unwanted waves contained in the digital signal or analog signal are reduced, and the input signal is input to the amplitude control device after amplitude adjustment so that unwanted waves are reduced.

[0011] [Method 3 for reducing unwanted signals] In the aforementioned unwanted wave reduction methods 1 and 2, if the input signal includes a multi-channel signal (multiple desired transmission waves; hereinafter simply referred to as "desired waves"), the digital signal can be separated according to the desired waves of different frequencies, the amplitude of each separated desired wave can be analyzed, and based on the analysis results, the amplitude range of the multi-wave amplitude control device can be adjusted so that unwanted waves included in each desired wave are reduced. The digital signal can then be input to the adjusted multi-wave amplitude control device so that unwanted waves included in each desired wave are reduced.

[0012] [Method 4 for reducing unwanted signals] The method for reducing unwanted waves in the present invention is a method for reducing unwanted waves by both frequency control using the bandpass filter and amplitude control using the amplitude control device.

[0013] (Signal transmission and reception device of the present invention) The signal transmitting and receiving device of the present invention comprises a transmission system that includes an analog-to-digital converter that converts an analog input signal into a digital signal, a digital-to-analog converter that converts a digital signal into an analog signal and outputs it, and a control system that detects unwanted waves contained in the digital signal transmitted by the transmission system and reduces them. The transmission system and the control system can be configured in various ways to reduce unwanted waves, but the transmission system and the control system have the following characteristics.

[0014] [Configuration of the transmission and control systems 1] The transmission system includes a bandpass filter that controls the frequency bandwidth of the input signal in front of the analog-to-digital converter, and the control system includes a frequency analyzer that analyzes the frequency of the digital signal. The control system is configured to automatically adjust the filtering bandwidth of the bandpass filter so that unwanted waves contained in the input signal are cut out, based on the analysis results from the frequency analyzer.

[0015] [Configuration of the transmission and control systems 2] The transmission system includes an amplitude control device that controls the amplitude of the input signal before the analog-to-digital converter, and the control system includes an analog power detection device or a digital power detection device. Based on the detection results of the analog power detection device or the digital power detection device, the amplitude range of the amplitude control device is automatically adjusted so that the amplitude of the input signal input to the analog-to-digital converter automatically fits within the dynamic range of the analog-to-digital converter.

[0016] [Transmission and Control System Configuration 3] The transmission system is equipped with both a bandpass filter that controls the frequency band of the input signal and an amplitude control device that controls the amplitude of the input signal in the preceding stage of the analog-to-digital converter. The control system includes a frequency analyzer that analyzes the frequency of the digital signal. Based on the analysis results from the frequency analyzer, the filtering band of the bandpass filter is automatically adjusted so that unwanted waves in the input signal are cut out, and the amplitude of the amplitude control device is automatically adjusted so that the amplitude of the input signal input to the analog-to-digital converter automatically fits within the dynamic range of the analog-to-digital converter.

[0017] [Configuration of the transmission and control systems 4] A subsequent stage of the analog-digital conversion device in the transmission system is provided with a desired wave separation device that separates multi-channel desired waves included in an input signal by desired wave, and a plurality of wave amplitude control devices that control the amplitude of each of the separated plurality of waves. The control system is provided with a plurality of wave power detection devices that detect the power (amplitude) of each of the desired waves separated by the desired wave separation device. According to the detection results of the plurality of wave power detection devices, the plurality of wave amplitude control devices automatically control the amplitude so that the amplitude of each desired wave falls within the dynamic range of the analog-digital conversion device.

Advantages of the Invention

[0018] The present invention has the following effects. (1) Even if there are unwanted waves in the desired wave band, the unwanted waves can be automatically detected and suppressed. Also, even if the frequency of the unwanted wave changes, it can automatically follow the change to reduce the unwanted wave. Therefore, even if the frequency of the unwanted wave changes at the location where the transmission and reception device is installed, the installer does not need to adjust. (2) Since the unwanted waves can be reduced before digitization, the processing load for reducing the unwanted waves included in the digitized signal is reduced. When sampling and digitizing the unwanted wave and the desired wave simultaneously, it is necessary to digitally implement a steep filter for suppressing the unwanted wave. Usually, a delay circuit and a multiplier of a digital circuit are frequently used for a steep filter. Therefore, by reducing the unwanted waves in advance before analog-digital conversion, the resources of the digital circuit (for example, the number of flip-flops and the number of multipliers such as FPGA) can be reduced, and the processing load is reduced. If the processing load is reduced, a cost reduction of the signal processing device can be expected. (3) For an input signal in which the frequencies of the unwanted wave and the desired wave are different, the slope of the frequency characteristic deteriorated by the band filtering device can be corrected according to the analysis result of the frequency characteristic analysis device of the digitized input signal. Therefore, except for the desired wave having the same frequency as the unwanted wave, the signal does not deteriorate. (4) Since there is an amplitude control device on the input side of the analog-to-digital conversion device, unnecessary power is not received by the analog-to-digital conversion device, the power of the desired wave can be increased within the reception range (large wave range) of the analog-to-digital conversion device, and the signal-to-noise ratio can be increased. (5) Since the influence of the adjacent channels of the band filtering device can be corrected by an equalization device, even if the desired wave is in the adjacent band, it can be passed through without degrading the signal characteristics. (6) In an analog-to-digital conversion device and an analog-to-digital conversion device having a wide sampling frequency with respect to the desired wave band, even if there are unwanted waves, the received power of a plurality of channels can be optimized respectively (7) Since there is a desired wave separation filtering device, the signal-to-noise ratio can be optimized by controlling the power of each channel, and the signal quality is less likely to deteriorate. (8) Since the amplification degree of the amplitude control device is not set to the maximum state when the input power is low, when input next time, it can be prevented that the output exceeds the upper limit range of the output and saturates, distortion occurs, or unwanted waves that have an adverse effect on adjacent channels are output.

Brief Description of Drawings

[0019]

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[0020] Embodiments of the signal transmission and reception method and signal transmission and reception device of the present invention will be described with reference to the drawings. The signal transmission and reception method of the present invention can be transmitted and received by various types of signal transmission and reception devices, but in the following description, the case in which transmission and reception are performed by the illustrated signal transmission and reception device will be described as an example.

[0021] (Embodiment 1 of the signal transceiver: Figure 1) Figure 1 shows one embodiment of the signal transmitting and receiving device of the present invention, which includes a bandpass filter 11 that passes signals in a predetermined frequency band in the input signal 10, an analog-to-digital converter 12 that converts the input signal into a digital signal, an equalizer 13 that corrects the frequency characteristics of the digitally converted digital signal, and a digital-to-analog converter 14 that converts the digital signal into an analog signal and outputs it 15 (hereinafter this path will be referred to as the "transmission system").

[0022] Figure 1 shows a frequency analyzer 16 that analyzes the frequency bandwidth characteristics of the entire digital signal converted by the analog-to-digital converter 12, and the digital signal Tip Power is detected Tip Power detection device 17, Tip The system also includes a determination device 18 that compares the output of the power detection device 17 with a reference value from the frequency reference device 20 to determine unwanted frequency signals (unwanted waves), and a frequency signal converter 19 that converts the frequency of the determined unwanted waves to the frequency of the adjustment signal of the bandpass filter device 11 (hereinafter this path will be referred to as the "control system").

[0023] General-purpose components can be used for the bandpass filter 11, analog-to-digital converter 12, equalizer 13, and digital-to-analog converter 14. The initial settings of the bandpass filter 11 are set to the lowest frequency, the highest frequency, etc., which are outside the receiving range band of the analog-to-digital converter 12 or outside the desired frequency band.

[0024] The bandpass filter 11 reduces unwanted signals included in the input signal that are within the sampling frequency band of the analog-to-digital converter 12, thereby keeping the total power within the receiving range and allowing adjustment of the filtering bandwidth.

[0025] The equalizer 13 has the function of restoring the frequency characteristics of the desired band that have been degraded by the bandpass filter 11 back to their original characteristics. By inputting the output of the judgment device 18 to update the coefficients, and then inputting the output of the analog-to-digital converter 12 to apply the updated coefficients, the frequency characteristics of the desired band that have been degraded by the bandpass filter 11 can be restored to their original state.

[0026] The equalization device 13 can use signal processing devices such as finite impulse response filters (FIR filters) or infinite impulse response filters (IIR filters). Typically, FIR filters are designed to achieve their effect by setting delay elements and filter coefficients, multiplying the input signal by the filter coefficients, and performing correlation calculations between the input signal and the filter coefficients. IIR filters are designed to set delay elements and filter coefficients, set feedback and feedforward to define the filter structure, approximate the filter characteristics from the structure, and correlate the filter characteristics with the input signal.

[0027] The equalizer 13 configures its characteristics by adaptively changing the filter coefficients using the least squares method or the like based on the output result of the determination device 18. The application method is not limited to this, and methods using a Kalman filter, recursive least squares method, neural network, etc., may also be used.

[0028] The frequency analyzer 16 can analyze the frequency versus power or phase of the output signal from the analog-to-digital converter 12. The frequency analyzer 16 may be a general-purpose device, or it may detect frequency characteristics using, for example, the Fast Fourier Transform, or it may detect the amplitude value of the DC component from the result of varying the output frequency of the numerically controlled oscillator and converting it to a DC component.

[0029] TipThe power detection device 17 detects unwanted waves present in either the unwanted or required frequency band from the output of the frequency analyzer 16. Tip It is capable of detecting electricity.

[0030] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 1] The signal transmission and reception method using the signal transmission and reception device shown in Figure 1 is described below. In Figure 1, of the input signal 10, only the signal within the passband of the bandpass filter 11 passes through the bandpass filter 11 and is input to the analog-to-digital converter 12 and converted into a digital signal. The frequency characteristics of the converted digital signal are modified by the bandpass filter 11. If the desired frequency band is suppressed near the band of the bandpass filter 11 (for example, the area enclosed by the dashed line in Figure 19(g)), the equalizer 13 corrects the characteristics of the required desired frequency band, and the desired frequency band characteristics of the output 15 of the digital-to-analog converter 14 (for example, the area enclosed by the dashed line in Figure 19(o)) become the bandwidth characteristics that can be received by the receiving device. The digital-to-analog converter 14 converts the signal-processed digital signal into an analog signal and outputs it 15.

[0031] Unwanted signals in the control system of the signal transceiver shown in Figure 1 are suppressed as follows. The digital signal, after passing through the bandpass filter 11 and being converted by the analog-to-digital converter 12, is separated and input to the frequency analyzer 16 for frequency analysis. Here, the overall frequency characteristics received by the analog-to-digital converter 12 are analyzed using Fourier transform, etc. If the power of unwanted waves is large, Tip High-power frequencies are determined to be frequencies that should be suppressed.

[0032] The output of the frequency analyzer 16 is Tip The power detection device 17 receives unwanted signals (unwanted waves). Tip Power is detected.

[0033] Tip The frequency of unwanted waves detected by the power detection device 17 is determined by the determination device 18 by comparing it with a reference value from the frequency reference device 20.

[0034] The output of the determination device 18 is input to the frequency signal converter 19. Based on the determination result of the determination device 18, the frequency signal converter 19 converts the frequency information into an adjustment value for the bandpass filter 11, thereby adjusting the characteristics of the bandpass filter 11 so that it gradually approaches the suppression band and suppresses unwanted waves (prevents unwanted waves from passing through). For example, if the adjustment value of the bandpass filter 11 is electrically between 0V and 1V and corresponds to 0.1MHz to 1000MHz, and the output of the determination device 18 is 300MHz, the frequency may be matched to a voltage such that it becomes 0.3V.

[0035] The characteristics of the bandpass filter 11 can sometimes attenuate frequency bands that are not intended to be filtered, potentially affecting signals in adjacent channels. Therefore, the equalizer 13 corrects the band characteristics of the desired wave to obtain appropriate band characteristics. The determination device 18 determines the frequency of unwanted waves from the necessary band information set by the frequency reference device 20, and from this information, it is possible to distinguish between suppressed and unsuppressed bands. The equalizer 13 may dynamically detect the band characteristics of the unwanted suppressed bands and restore them to their original band characteristics, or it may be pre-configured with inverse characteristics for the unwanted suppressed band characteristics of the bandpass filter 11.

[0036] [Unnecessary wave] There are various states of unwanted signals within the reception range of the analog-to-digital converter 12, but as an example, two types of states will be described. Other states, for example, outside the reception range of the analog-to-digital converter 12 (outside the first Nyquist zone), can also be recognized as follows.

[0037] [When unwanted signals exist in a different frequency band than the desired signal] The case where unwanted waves exist in a different frequency band than the desired wave will be explained using the waveform diagram in Figure 19.

[0038] Figures 19(a) to (h) and (o) are waveform diagrams of the points (a) to (h) and (o) in Figure 1. Figure 19(a) is the waveform diagram of the input signal to the bandpass filter 11. The input signal in Figure 1 is for multiple channels (5 channels as an example) (the same applies in the following explanation). Figure 19(b) is the waveform diagram of the initial value (initial characteristics: the same applies hereafter) of the bandpass filter 11, Figure 19(c) is the waveform diagram of the output signal of the analog-to-digital converter 12, Figure 19(d) is the waveform diagram of the output signal of the frequency analyzer 16, Figure 19(e) is the waveform diagram of the initial value of the equalizer 13, Figure 19(f) is the waveform diagram of the bandpass filter 11 after judgment, Figure 19(g) is the waveform diagram of the output signal of the digital-to-analog converter 14 before judgment, Figure 19(h) is the waveform diagram of the equalizer 13 after judgment, and Figure 19(o) is the waveform diagram of the output signal of the digital-to-analog converter 14 after judgment.

[0039] In Figures 19(a) to (h) and (o), the vertical axis in the 1000 direction represents the level, and the horizontal axis in the 1001 direction represents the frequency. Reference numeral 1002 indicates unwanted waves, and reference numeral 1003 indicates desired waves. Reference numeral 1004 represents the characteristics of the bandpass filter 11 (e.g., notch characteristics), and the initial value is the setting of the lowest frequency, highest frequency, or out-of-band frequency of the analog-to-digital converter 12. Reference numeral 1005 represents the quantization noise of the analog-to-digital converter 12. Reference numeral 1006 is Tip Detected by power detection device 17 Tip This is power. Code 1007 indicates the channel of the determined desired wave. Code 1008 is the initial value of the characteristics of the equalizer 13, and code 1009 is the characteristics of the equalizer 13 after determination.

[0040] In Figure 1, the determination device 18 detects the frequency of unwanted waves and changes the characteristics of the bandpass filter 11 from (b) to (f). At the same time, the determination device 18 notifies the equalizer 13 of the change, and the equalizer 13 corrects the characteristics of the desired frequency band from (e) to (h).

[0041] The analysis results from the frequency analyzer 16 showed that unwanted waves exist in a different frequency band than the desired wave. TipThe detection result from the power detection device 17 can be used to determine the frequency band. The frequency band is then notified to the determination device 18. The determination device 18 outputs the adjustment value of the bandpass filter 11 in that frequency band. If the adjustment value is output too quickly, the suppression band will fluctuate rapidly, which may cause unwanted waves to be suppressed instantaneously or to suddenly reappear, making the analysis results of the frequency analysis device 16 unstable. Therefore, the determination device 18 adjusts the adjustment value to gradually approach the unwanted wave. The frequency reference device 20 outputs a reference value that serves as a standard for separating the desired wave from the unwanted wave, by notifying the channel of the desired wave from a control device (not shown), a central control device (CPU), etc.

[0042] [If unwanted waves are present within the desired frequency band] The state of each device in Figure 1 will be explained using Figures 20(a) to (h) and (o) when unwanted waves are present within the desired frequency band. Figures 20(a) to (h) and (o) are explanatory diagrams of the state 2 of unwanted waves in the signal transmitting and receiving device in Figure 1. Figure 20(a) is the waveform of the input signal to the bandpass filter 11, Figure 20(b) is the waveform of the initial value of the bandpass filter 11, Figure 20(c) is the waveform of the output signal of the analog-to-digital converter 12, Figure 20(d) is the output signal of the frequency analyzer 16, Figure 20(e) is the waveform of the initial value of the equalizer 13, Figure 20(f) is the waveform after the bandpass filter 11 has made its determination, Figure 20(g) is the waveform of the output signal of the digital-to-analog converter 14 before its determination, Figure 20(h) is the waveform after the equalizer 13 has made its determination, and Figure 20(o) is the waveform of the output signal of the digital-to-analog converter 14 after its determination. The symbols in Figure 20 are the same as those in Figure 19.

[0043] As shown in Figure 20(a), since the desired signal also exists at frequencies where unwanted signals are present, the desired signal becomes unreceivable. When frequencies with unwanted signals are suppressed by the bandpass filter 11 as shown in Figure 20(g), it becomes necessary to correct the characteristics of the signal in the adjacent channel. Therefore, the equalizer 13 corrects the band characteristics of the desired signal in the adjacent channel as shown in Figure 20(h).

[0044] Even if unwanted signals exist outside the receiving band of the digital-to-analog converter and outside the first Nyquist zone, they can be treated in the same way as when unwanted signals exist in a different band than the desired signal, or when unwanted signals exist within the desired signal band.

[0045] (Embodiment 2 of the signal transceiver: Figure 3) Figure 3 shows a second embodiment of the signal transmitting and receiving device of the present invention, the basic configuration being the same as that of the signal transmitting and receiving device in Figure 1. The difference from the signal transmitting and receiving device in Figure 1 is that the frequency reference device 20 in Figure 1 has been replaced with a demodulation / decoding device 21 in order to automatically identify the desired wave. The demodulation / decoding device 21 demodulates the modulated wave when the input signal to the equalizer 13 is a modulated wave, and inputs the demodulated wave to the determination device 18. The demodulation / decoding device 21 has a function to detect whether the demodulated signal is a demodulation-readable signal.

[0046] If unwanted signals are present in the desired frequency band, the frequency reference device 20 in Figure 1 requires a method to distinguish its output from the signals of each channel and the unwanted signals. It needs a means to observe the state of each desired signal and automatically suppress the signal if it becomes unreceivable due to unwanted signals. In Figure 3, the demodulation / decoding device 21 can determine if the signal is normal if it can be demodulated and decoded, or if it is an unwanted signal if it cannot.

[0047] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 3] A signal transmission and reception method using the signal transmission and reception device shown in Figure 3 will be explained based on Figures 3 and 4. This signal transmission and reception method is basically the same as signal transmission using the signal transmission and reception device in Figure 1 (flowchart in Figure 2). The difference is that when the input signal to the equalizer 13 is a modulated wave, the modulated wave is demodulated by the demodulation / decoding device 21, and the demodulated wave is input to the determination device 18. As a result, the determination device 18 compares the input signal from the demodulation / decoding device 21 with a reference value to determine unwanted signals, and the output of the determination device 18 (signal in the desired bandwidth) is input to the equalizer 13. The frequency characteristics of the equalizer 13 are calculated from the frequency characteristics of the desired bandwidth, and the characteristics of the necessary signals are corrected in the equalizer 13.

[0048] [Example of changes in Figure 3] The demodulation / decoding device 21 in Figure 3 can be replaced with other means that can determine whether the desired signal is receivable. In this case, the operation is the same as the flowchart in Figure 4.

[0049] (Embodiment 3 of the signal transceiver: Figure 5) Figure 5 shows a third embodiment of the signal transmission and reception device of the present invention, which, like the case in Figure 1, includes a transmission system and a control system.

[0050] The transmission system in Figure 5 includes an amplitude control device 101 that controls the amplitude of the input signal, an analog-to-digital converter 12, a desired wave separation filter 102 that separates the digital signal into multiple desired waves, a multiple wave amplitude control device 103 that controls the amplitude of each of the multiple desired waves, and a digital-to-analog converter 14 that converts the amplitude-controlled multiple digital signals into analog signals and outputs them 15.

[0051] The control system shown in Figure 5 includes an analog power detection device 104, an analog control device 105, a power signal converter 106, an analog reference control device 111, a multi-wave input power detection device 107, a multi-wave reference control device 108, a multi-wave power detection device 109, and a multi-wave control device 110.

[0052] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 5] The signal transmission and reception method using the signal transmission and reception device shown in Figure 5 is described below. Figures 21(i) to (n) are waveform diagrams for each point in Figure 5 (i) to (n). Figure 21(i) is the waveform diagram of the input signal of the amplitude control device 101, Figure 21(j) is the waveform diagram of the output signal of the analog-to-digital converter 12, Figure 21(k) is the waveform diagram of the output signal of the amplitude control device 101 controlled by the output of the power signal converter 106, Figure 21(l) is the waveform diagram of the output signal of the desired wave separation filter 102, Figure 21(m) is an example of the waveform diagram of the output signal of the multi-wave amplitude control device 103, and Figure 21(n) is the waveform diagram of the output signal of the digital-to-analog converter 14.

[0053] In Figure 5, the multiple input signals (five channels as an example) exhibit amplitude fluctuations (dashed lines in Figure 21(i)). The analog-to-digital converter 12 has a wide bandwidth sampling frequency, allowing it to acquire multiple channels simultaneously (Figure 21(i)). In Figure 21(i), 1010 shows the amplitude fluctuation, and 1003 shows the amplitude bandwidth of the desired wave. The desired wave separation filter 102 can, for example, use an FIR filter to separate the five channels into their respective channel signals, outputting them as one channel per signal, and decimating the sampling frequency to match each channel (Figure 21(l)). For example, in Figure 21(i), the central signal (shown in white) can have unwanted waves originating from the input signal reduced by the amplitude control device 101, but the multi-wave amplitude control device 103 in Figure 5 can further reduce unwanted waves through faster control within a range that does not degrade the signal (Figures 21(l) to (m)). The filter for the desired wave separation filter 102 is not limited to an FIR filter; it may also be an IIR filter or other type of filter. Furthermore, the method for removing unwanted waves is not limited to these.

[0054] In the signal transmission system of the signal transceiver shown in Figure 5, signal transmission is performed as follows. The amplitude of the input signal 10 is amplified or attenuated in the amplitude control device 101 according to the adjustment value of the amplitude control device 101, and is contained within the dynamic range of the analog-to-digital converter 12. The signal is then input to the analog-to-digital converter 12 and converted into a digital signal. The digital signal is separated into multiple channel signals (desired waves) in the desired wave separation filter 102. Each of the separated desired waves in the multiple channel is input to the multi-wave amplitude control device 103 for amplitude control, converted into an analog signal by the digital-to-analog converter 14, and output 15.

[0055] In the control system of the signal transceiver shown in Figure 5, the suppression of unwanted wave signals is performed as shown in the flowchart in Figure 6. The amplitude-controlled input signal from the amplitude control device 101 is input to the analog power detection device 104 to detect the power of the input signal. The detected power is then controlled by the analog control device 105 so that it matches the reference value from the analog reference control device 111, and adjusted so as not to exceed the power reception range of the analog-to-digital converter 12.

[0056] The output of the analog control device 105 is converted into an amplitude control signal by the power signal converter 106 and input to the amplitude control device 101. This input updates the threshold of the amplitude control device 101 so that it can control the amplitude of the input signal whose amplitude changes in real time.

[0057] The inclusion of the analog control device 105 between the amplitude control device 101 and the analog-to-digital converter 12 increases the path length, and the control time from the analog power detection device 104 to the amplitude control device 101 also increases, making high-speed operation impossible.

[0058] The multi-wave input power detection device 107 sets the reference value of the analog reference control device 111 to a specific value when the signal received by the analog-to-digital converter 12 is of a certain value, for example, when it detects power that does not reach the power required for signal transmission, or when the value is large compared to a threshold. For example, this could be the control value of the multi-wave control device 110 at that time, or a control value that outputs low power. This prevents the amplification of the multi-wave amplitude control device 103 from reaching its maximum (saturated) state when the power of individual channels is lower than a threshold. This embodiment is merely an example of the present invention, and other methods may be used as long as they prevent the amplification of the multi-wave amplitude control device 103 from reaching its maximum state when the input power is low. The multi-wave amplitude control device 103 basically operates to amplify the power of the input signal, but the above operation is the opposite: when the power is low or relative to a certain threshold, it lowers the amplification, sets it to a specific value, or does not amplify at all.

[0059] The details of the above operation will be described. The output power of the desired wave separation and filtering device 102 is detected by the multi-wave input power detector 107. When the power value input to the multi-wave input power detector 107 is below a certain level, the target amplitude value is changed (lowered) from the multi-wave reference control device 108, so the reference level drops and the amplitude increase does not reach the maximum. That is, let the input power of the input signal be X. At this time, let the gain of the multi-wave amplitude control device 103 be G, the target power be P, and the output power be Y. Also, if the noise contained in the input power X is Nx, then X > Nx and Y = GX + GNx. The relationship between the target power and the output is P = Y. When there is no multi-wave input power detector 107 and X is 0 and only Nx is included, when the input signal is below a certain level, the gain G becomes the maximum Gm. Since G < Gm and the output is 0 because there is no input signal, but the noise Nx is received, so Y = GmNx. The relationship between the target power and the output power is P > Y. In this state, it is held. When the input power X is suddenly input, instantaneously Y = GmX + GmNx and P > Y. Since the maximum level is input to the digital-to-analog converter 14, there is a risk of distortion in the signal. Here, when it is below a certain value Z detected by the multi-wave input power detector 107, a new target power Pu is set. Pu < P. When P is changed to Pu when the input signal X is below Z, since the target power drops, the gain becomes Gu. The output power Y is GuNx. Pu = Y. When X is input, the output power Y is GuX + GuNx. Since Pu < P, there is no risk that the analog-to-digital converter 12 will saturate. After that, when it is detected that X is above Z and Pu is returned to P, since X has already been input, Y = G X + GNx and there is no saturation, so no distortion occurs in the signal.

[0060] The power of each channel separated by the desired wave separation filter 102 is measured by the multi-wave input power detection device 107, and its output is input to the multi-wave reference control device 108, and the reference value from the multi-wave reference control device 108 is input to the multi-wave control device 110. At this time, the multi-wave input power detection device 107 detects the power of each individual channel contained in the digitized input signal and inputs the detection result to the multi-wave control device 110. Based on both input signals, the multi-wave control device 110 operates by comparing the current amplitude control value with the reference value and bringing it closer to the control value of the multi-wave power detection device 109. When the output of the multi-wave control device 110 is input to the multi-wave amplitude control device 103, the multi-wave input power detection device 107 compares the output power of the desired wave separation filter 102 with a threshold, and if the input power is low, sets the reference value to a specific value.

[0061] The multi-wave amplitude control device 103 is updated at a faster timing than the amplitude control device 101, which allows for stabilization even if the power of the input signal changes rapidly due to fading or other factors.

[0062] The amplitude control device 101 operates in such a way that the analog-to-digital converter 12 does not distort when the amplitude fluctuation changes slowly, while the multi-wave amplitude control device 103 operates in such a way that the output stabilizes when the amplitude changes of each channel are fast.

[0063] (Embodiment of signal transceiver 4: Figure 7) Figure 7 shows Embodiment 4 of the signal transmitting and receiving device of the present invention, and its basic configuration is the same as that of Figure 5. The difference is that an input power detection device 112, an input power determination device 113, and a determination result conversion device 114 have been added to the configuration of Figure 5.

[0064] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 7] The signal transmission and reception method using the signal transceiver shown in Figure 7 will be explained based on Figure 8. Since the configuration of the signal transceiver in Figure 7 is basically the same as that of the signal transceiver in Figure 5, its operation (flowchart in Figure 8) is also basically the same as that of the transceiver in Figure 5 (flowchart in Figure 6). The differences are as follows:

[0065] In the signal transceiver shown in Figure 7, the power of the input signal 10 is detected by the input power detection device 112 and input to the input power determination device 113, and the output of the determination result conversion device 114 is input to the analog reference control device 111. The rest is the same as in Figure 5, and the analog control device 105 controls the detected power so that it is the same as the reference value from the analog reference control device 111, and is adjusted so as not to exceed the power reception range of the analog-to-digital converter 12. The output of the analog control device 105 is converted into an amplitude control signal by the power signal conversion device 106, and this signal is input to the amplitude control device 101, and the threshold of the amplitude control device 101 is updated so that the amplitude of the input signal, which changes in amplitude as it occurs, can be controlled.

[0066] The multi-wave input power detection device 107, multi-wave reference control device 108, multi-wave control device 110, and multi-wave amplitude control device 103 of the signal transceiver shown in Figure 7 operate in the same manner as those shown in Figure 5. However, since the extraction of input power, which is in the analog signal domain, involves losses, the determination value is set taking these losses into account.

[0067] (Embodiment of signal transceiver 5: Figure 9) Figure 9 shows Embodiment 5 of the signal transmission and reception device of the present invention, and its configuration is basically the same as that of Figure 7. The difference is that the analog power detection device 104 in Figure 7 is replaced with a digital power detection device 134, and the digital power detection device 134 is provided on the output side of the analog-to-digital converter 12.

[0068] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 9] The signal transmission and reception method using the signal transmission and reception device in Figure 9 is shown in the flowchart in Figure 10. The signal transmission and reception device in Figure 9 has basically the same configuration as the transmission and reception device in Figure 7, so its operation (flowchart in Figure 10) is basically the same as the operation of the transmission and reception device in Figure 7 (flowchart in Figure 8). The difference is that the output of the digital power detection device 134 is input to the digital control device 135.

[0069] The operation of the signal transceiver in Figure 9 will be explained based on the waveform diagrams in Figures 21(i) to (n). Figures 21(i) to (n) are waveform diagrams for each point in Figure 9 (i) to (n). In Figure 21, the vertical axis (labeled 1000) represents the level, and the horizontal axis (labeled 1001) represents the frequency. The dashed lines in the figures indicate the case where fading (level fluctuation) occurs.

[0070] Figure 21(i) shows the input signal of the amplitude control device 101 in Figure 9, Figure 21(j) shows the output signal of the analog-to-digital converter 12, Figure 21(k) shows the output signal of the amplitude control device 101 controlled by the output of the power signal converter 106, Figure 21(l) shows the output signal of the desired wave separation filter 102, Figure 21(m) shows an example of the output signal of the multi-wave amplitude control device 103, and Figure 21(n) shows the output signal of the digital-to-analog converter 14.

[0071] In Figure 21(i), the symbol 1010 indicates an input signal that is fading or has amplitude fluctuations, and the symbol 1003 indicates the desired signal. In the signal transceiver in Figure 9, the output signal of the analog-to-digital converter 12 has its gain adjusted within the receiving amplitude range of the analog-to-digital converter 12 in Figure 9. In Figure 21(j), the symbol 1011 indicates the amplitude receivable range of the analog-to-digital converter 12.

[0072] The waveform diagram in Figure 21(k) is the waveform diagram after the total power has been detected by the digital power detection device 134 and digital control device 135 in Figure 9, and adjusted by the amplitude control device 101 to reduce the overall amplitude fluctuation.

[0073] In Figure 21(l), 1012 represents the signals of each channel separated by the desired wave separation filter 102 in Figure 9.

[0074] Figure 21(m) shows the amplitude control of a separated single channel.

[0075] Figure 21(n) shows the output signal in Figure 9. In Figure 21(n), the symbol 1013 indicates the transmission amplitude range. The symbol 1005 is the quantization noise generated in the analog-to-digital converter 12.

[0076] (Embodiment 6 of the signal transceiver: Figure 11) Figure 11 shows a sixth embodiment of the signal transmitting and receiving device of the present invention, which includes a transmission system and a control system, and its configuration is basically the same as the signal transmitting and receiving device in Figure 7. The differences are that the analog power detection device 104 in Figure 7 is replaced with a digital power detection device 134, the analog control device 105 in Figure 7 is replaced with a digital control device 135 for control in the digital domain, the analog reference control device 111 in Figure 7 is replaced with a digital reference control device 131 for outputting a reference value in the digital domain, and the digital power detection device 134 is provided on the output side of the analog-to-digital converter 12.

[0077] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 11] The signal transmission method using the signal transceiver in Figure 11 is shown in the flowchart in Figure 12. The transceiver in Figure 11 has basically the same configuration as the transceiver in Figure 7, so its operation (flowchart in Figure 12) is basically the same as the operation of the transceiver in Figure 7 (flowchart in Figure 8). The difference is that the output of the digital power detection device 134 is input to the digital control device 135. In addition, since the result detected by the input power detection device 112 is input to the digital reference control device 131, it is desirable to add a judgment result conversion device 114 to the judgment device and use another digital-to-analog conversion device 14, or use a different protocol to convert it to a digital signal.

[0078] (Embodiment 7 of the signal transceiver: Figure 13) Figure 13 shows Embodiment 7 of the signal transmitting and receiving device of the present invention, which includes a transmission system and a control system. A feature of this signal transmitting and receiving device is that the transmission system is equipped with both a bandpass filter 11 and an amplitude control device 101.

[0079] The transmission system in Figure 13 includes a bandpass filter 11 and an amplitude control device 101 that controls the amplitude of the input signal on the input side of the analog-to-digital converter 12, and on the output side a desired wave separation filter 102 that separates the digital signal into multiple desired waves, a multiple wave amplitude control device 103 that controls the amplitude of each of the multiple desired waves, and a digital-to-analog converter 14 that converts the amplitude-controlled multiple digital signals into analog signals and outputs them 15.

[0080] As shown in Figure 13, by providing the bandpass filter 11, unwanted signals in the input signal are suppressed before digital-to-analog conversion. Subsequently, the amplitude is controlled by the amplitude control device 101 to bring it within the receivable amplitude range for the analog-to-digital converter 12, and then the analog-to-digital converter 12 performs the digital conversion.

[0081] The control system in Figure 13 has a frequency analyzer 16 on the output side of the analog-to-digital converter 12 and an input side of the desired wave separation and filtering device 102, with multiple waves on the output side of the frequency analyzer 16. Tip The system includes a power detection device 137, a determination device 18, a frequency signal converter 19, a frequency reference device 20, a digital control device 135, a power signal converter 106, and a digital reference control device 131.

[0082] The frequency analyzer 16 can analyze the frequency-to-power or phase characteristics of the output signal from the analog-to-digital converter 12. Tip The power detection device 137 detects unwanted waves present in either the unwanted or required frequency band from the output of the frequency analyzer 16. Tip It is capable of detecting electricity.

[0083] Figure 13 shows the frequency analyzer 16 and multiple waves. TipThe power detection device 137 has the function of detecting the frequency information of unwanted waves and the total power input to the analog-to-digital converter 12, and the bandpass filter 11 and the amplitude control device 101 can be operated simultaneously and with separate frequency characteristics. Furthermore, abrupt changes in each channel can be stabilized by the multi-wave amplitude control device 103. At this time, by optimizing the output power level for the digital-to-analog converter 14, the signal-to-noise ratio of the output signal can be suitably determined. In this invention, the amplitude control device 101 may be placed after the digital-to-analog converter 14 to stabilize the output signal which has become an analog signal.

[0084] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 13] The operation of the signal transceiver shown in Figure 13 is as shown in the flowchart in Figure 14. The input signals in Figure 13 are also multi-channel signals, and the levels of one or more signals are fluctuating.

[0085] In Figure 13, of the input signal 10, only the signal within the passband of the bandpass filter 11 passes through the bandpass filter 11 and is input to the amplitude control device 101, where the amplitude of the input signal is amplified or attenuated according to the adjustment value of the amplitude control device 101, and is contained within the dynamic range of the analog-to-digital converter 12. The analog-to-digital converter 12 then inputs the signal and converts it into a digital signal. The digital signal is separated into multiple channel signals (desired waves) in the desired wave separation filter 102. Each of the separated desired waves in the multiple channel is input to the multi-wave amplitude control device 103 for amplitude control, and then converted into an analog signal by the digital-to-analog converter 14 and output.

[0086] In the control system of the signal transceiver shown in Figure 13, unwanted signals are suppressed as follows. The digital signal, which passes through the bandpass filter 11, is amplitude-controlled by the amplitude control device 101, and converted by the analog-to-digital converter 12, is frequency-analyzed by the frequency analyzer 16. Here, the overall frequency characteristics received by the analog-to-digital converter 12 are analyzed using Fourier transform, etc. If the power of the unwanted wave is large, Tip High-power frequencies are determined to be frequencies that should be suppressed.

[0087] The output of the frequency analyzer 16 is multiple waves. Tip The power detection device 137 receives unwanted signals (unwanted waves). Tip Power is detected.

[0088] Multiple waves Tip The frequency of the unwanted signal detected by the power detection device 137 is determined by the determination device 18 by comparing it with a reference value from the frequency reference device 20.

[0089] The output of the determination device 18 is input to the frequency signal converter 19, and the frequency signal converter 19 converts the frequency information to the adjustment value of the bandpass filter 11 based on the determination result of the determination device 18, thereby adjusting the characteristics of the bandpass filter 11 so that it gradually approaches the suppression band and suppresses unwanted waves (does not allow unwanted signals to pass through). The determination device 18 determines the frequency of unwanted waves from the information of the necessary band set by the frequency reference device 20, and from that information it can distinguish between the suppressed band and the unsuppressed band.

[0090] The output of the digital control device 135 is converted into an amplitude control signal by the power signal converter 106 and input to the amplitude control device 101, and the threshold of the amplitude control device 101 is updated so that it can control the amplitude of the input signal whose amplitude changes in real time.

[0091] The multi-wave input power detection device 107 sets the reference value of the digital reference control device 131 to a specific value when the signal received by the analog-to-digital converter 12 is at a specific value, for example, when it detects a power level that does not reach the power required for signal transmission, or when the value is large compared to a threshold. For example, this could be the control value of the multi-wave control device 110 at that time, or a control value that outputs low power. This prevents the amplification of the amplitude control device 101 from reaching its maximum state when the power of individual channels is lower than the threshold. The amplitude control device 101 basically operates to amplify the power of the input signal, but the above operation is the opposite: when the power is low or a certain threshold is exceeded, the amplification is reduced, set to a specific value, or no amplification is performed.

[0092] The power of each channel separated by the desired wave separation filter 102 is measured by the multi-wave input power detection device 107, and its output is input to the multi-wave reference control device 108, and its (reference value) is input to the multi-wave control device 110. At this time, the multi-wave power detection device 109 detects the power of each individual channel included in the digitized input signal and inputs the detection result to the multi-wave control device 110. Based on both input signals, the multi-wave control device 110 operates by comparing the current amplitude control value with the reference value and bringing it closer to the control value of the digital reference control device 131. The output of the multi-wave control device 110 is input to the multi-wave amplitude control device 103. In the multi-wave amplitude control device 103, the input power is compared with a threshold, and if the input power is low, the reference value is set to a specific value.

[0093] The multi-wave amplitude control device 103 is updated at a faster timing than the amplitude control device 101, which allows for stabilization even if the power of the input signal changes rapidly due to fading or other factors.

[0094] The amplitude control device 101 operates in such a way that the analog-to-digital converter 12 does not distort when the amplitude fluctuation changes slowly, while the multi-wave amplitude control device 103 operates in such a way that the output stabilizes when the amplitude changes of each channel are fast.

[0095] (Embodiment of signal transceiver 8: Figure 15) Embodiment 8 of the signal transmitting and receiving device of the present invention is shown in Figure 15, and is the signal transmitting and receiving device of Figure 13 with the addition of a multi-wave equivalent device 121, a multi-wave input power detection device 120, an input power determination device 113, and a determination result conversion device 114.

[0096] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 15] The signal transmission and reception method using the signal transceiver shown in Figure 15 is as shown in the flowchart in Figure 16. It is basically the same as the signal transmission method using the signal transceiver shown in Figure 13, but differs in the following points.

[0097] One difference is that, by providing a multi-wave input power detection device 120, an input power determination device 113, and a determination result conversion device 114, a portion of the input signal is branched and input to the multi-wave input power detection device 120 for power detection. The detected power is input to the input power determination device 113 and the determination result conversion device 114. The determination result is input to the digital reference control device 131, and the power signal conversion device 106 controls it so that it becomes the same power as the reference value of the amplitude control device 101, and adjusts it so that it does not exceed the power reception range of the analog-to-digital converter 12. As a result, the internal gain of the amplitude control device 101 is not maximized when the input power is very small, and even if the input power is suddenly input, it will not exceed the receivable power range of the analog-to-digital converter 12.

[0098] Another difference is that, by providing the multi-wave equivalent device 121, it becomes possible to correct the in-band characteristics of the desired wave for each channel, similar to the signal transceiver in Figure 1 (a signal transceiver equipped with an equalizer 13), and the characteristics of adjacent desired waves that were suppressed by the bandpass filter 11 are automatically improved.

[0099] (Embodiment of signal transceiver 9: Figure 17) Embodiment 9 of the signal transceiver of the present invention has the configuration shown in Figure 17. The basic configuration is the same as that of the signal transceiver in Figure 15, the only difference being that a demodulation / decoding device 21 is provided instead of the frequency reference device 20 of the signal transceiver in Figure 15. The demodulation / decoding device 21 demodulates a modulated wave when the input signal to the multi-wave equalizer 121 (Figure 17) is a modulated wave, and inputs the demodulated wave to the determination device 18. The demodulation / decoding device 21 has the function of automatically determining whether the desired wave can be received. Here, any device that can confirm the state of the desired wave may be used instead of the demodulation / decoding device 21, such as a means that can measure channel power or a means that can confirm the pilot signal included in the signal.

[0100] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 17] The signal transmission and reception method using the signal transmission and reception device shown in Figure 17 is as shown in Figure 18, and is basically the same as the operation in Figure 15. The difference is that, by providing a demodulation / decoding device 21, the demodulation / decoding device 21 not only outputs a reference signal but can also automatically determine whether the desired signal can be received.

[0101] The signal transmission and reception method using the signal transmission and reception device shown in Figure 17 will be explained based on the signal waveform diagrams in Figures 22(i) to (n).

[0102] Figure 22(i) shows the waveform of the input signal output from the bandpass filter 11 in Figure 17, where the amplitude and phase fluctuate in one or more channels of unwanted and desired signals.

[0103] Figure 22(i) shows the initial waveform of the frequency characteristics of the bandpass filter 11 in Figure 17, which is set to a specific frequency, either the frequency of the desired wave or outside the receiving band of the analog-to-digital converter 12.

[0104] Figure 22(j) is a waveform diagram of the output of the analog-to-digital converter 12 in Figure 17, with quantization noise 1005 generated during digitization added.

[0105] Figure 22(j) shows the waveform of the initial output of the frequency analyzer 16, and is a multiple wave diagram of Figure 17. Tip The information detected by the power detection device 137 is output.

[0106] Figure 22(l) is a waveform diagram of the initial values ​​of the correction characteristics of the multi-wave equalizer 121 shown in Figure 17.

[0107] Figure 22(k) shows the frequency characteristics of the bandpass filter 11 in Figure 17, illustrating the control value of the bandpass filter 11 and its characteristics as they change due to feedback.

[0108] Figure 22(m) is a waveform diagram at point (m) in Figure 17, showing the characteristics of the corrected desired wave when the correction characteristics of the multi-wave equalizer 121 are corrected.

[0109] Figure 22(n) is the waveform diagram at point (n) in Figure 17, and is the waveform after the multi-wave equalizer 121 corrects the frequency characteristics based on the results of the frequency analyzer 16 and the multi-wave power detector 109 using control values ​​set by feedback and feedforward, and then converts it by the digital-to-analog converter 14.

[0110] Figure 22(n) shows how the signal-to-noise ratio is improved by the effects of the multi-wave amplitude control device 103 and the multi-wave equalizer 121.

[0111] The above explanation assumes a single channel of unwanted signals, but the same operation applies even when multiple channels of unwanted signals are present.

[0112] (Embodiment 10 of the signal transceiver: Figure 23) Figure 23 shows Embodiment 10 of the signal transmitting and receiving device of the present invention, characterized by the inclusion of both a bandpass filter 11 and an amplitude control device 101 that automatically adjusts the signal to fit within the dynamic range of the analog-to-digital converter 12. In Figure 23, as in Figure 1, the device includes an analog-to-digital converter 12 that converts the input signal into a digital signal, an equalizer 13 that corrects the frequency characteristics of the digitally converted digital signal, and a digital-to-analog converter 14 that converts the digital signal into an analog signal and outputs it 15 (transmission system).

[0113] Figure 23 shows a frequency analyzer 16 that analyzes the overall frequency bandwidth characteristics of the digital signal converted by the analog-to-digital converter 12, similar to the case in Figure 1, and the digital signal Tip Power is detected Tip Power detection device 17, Tip The system includes a determination device 18 that compares the output of the power detection device 17 with a reference value from the frequency reference device 20 to determine unwanted frequency signals (unwanted waves), and a frequency signal converter 19 that converts the frequency of the determined unwanted waves to the frequency of the adjustment signal of the bandpass filter 11 (control system). Also, similar to the case in Figure 9, the system includes a digital power detection device 134 that detects the digital power of the entire digital signal converted by the analog-to-digital converter 12, a digital control device 135, a digital reference control device 131, and a power signal converter 106 (control system).

[0114] The equipment shown in Figure 23 can be the same as the equipment with the same name shown in Figures 1 and 9.

[0115] [Signal transmission and reception method using the signal transmission and reception device shown in Figure 23] The operation of the signal transmitting and receiving device in Figure 23 is shown in the flowchart in Figure 24. In Figure 23, of the input signal 10, only the signal within the passband of the bandpass filter 11 passes through the bandpass filter 11. After passing through, it is input to the amplitude control device 101, where the amplitude of the input signal is amplified or attenuated according to the adjustment value of the amplitude control device 101, and is placed within the dynamic range of the analog-to-digital converter 12.

[0116] The digital signal converted by the analog-to-digital converter 12 is frequency-analyzed by the frequency analyzer 16. The output of the frequency analyzer 16 is Tip This is input to the power detection device 17. Here, Tip High-power frequencies are determined to be unwanted frequencies that should be suppressed. Frequencies determined to be unwanted are compared by the determination device 18 with a reference value from the frequency reference device 20. The output of the determination device 18 is input to the frequency signal converter 19, and the frequency signal converter 19 converts the frequency information into adjustment values ​​for the bandpass filter 11 based on the determination result of the determination device 18. This adjusts the characteristics of the bandpass filter 11 so that it gradually approaches the suppression band and suppresses unwanted frequencies (prevents unwanted signals from passing through).

[0117] The digital power detection device 134 detects the total power of the digital signal, and the digital control device 135 controls the detected power so that it matches the reference value from the digital reference control device 131. The output of the digital control device 135 is converted into an amplitude control signal by the power signal converter 106, and this signal is input to the amplitude control device 101, which updates the threshold of the amplitude control device 101 so that it can control the amplitude of the input signal whose amplitude changes in real time. [Industrial applicability]

[0118] The embodiments described above are the main examples of the present invention. The present invention is not limited to these embodiments, and the design can be modified to the extent that the problem can be solved. In Figures 1 to 24, devices with the same reference numerals as those in other figures have the same configuration and function. The devices of the present invention can also be replaced with other devices having the same function as the illustrated devices. The present invention can also be used in art fields other than those described above. [Explanation of Symbols]

[0119] 10 input signals 11. Bandpass Filtering Device 12 Analog-to-Digital Converter 13 Equalizer 14. Digital-to-analog converter 15 Output signal 16. Frequency analyzer 17 Tip Power detection device 18 Judgment device 19. Frequency signal converter 20 Frequency Reference Device 21 Demodulation / Decoding Device 101 Amplitude control device 102 Desired wave separation filter device 103 Multiple-wave amplitude control device 104 Analog power detection device 105 Analog control device 106 Power signal converter 107 Multiple-wave input power detection device 108. Multiple-wave reference control device 109 Multiple-wave power detection device 110 Multiple-wave control device 111 Analog Reference Control Unit 112 Input power detection device 113 Input Power Determination Device 114. Judgment Result Conversion Device 120 Multiple-wave input power detection device 121 Multiple-wave equalizer 131 Digital Reference Control System 134 Digital Power Detection Device 135 Digital control device 137 Multiple waves Tip It should be noted that there seems to be a duplicate "Tip " in the original text which might be a typo. I've translated it as is. Also, the "[[ID=z2]]" in the original might be an error, it's translated as "

Figure 23

Claims

1. This is a signal transmission and reception method in which an analog input signal is converted to a digital signal using an analog-to-digital converter, unwanted signals contained in the input signal and digital signal are reduced, and then the signal is converted back to an analog signal using a digital-to-analog converter and output. The frequency bandwidth of the input signal is brought within the sampling frequency bandwidth of the analog-to-digital converter by a bandpass filter, and the total power is brought within the receiving range of the analog-to-digital converter to reduce unwanted waves. The frequency after digital conversion is analyzed, and based on the analysis results, the filtering bandwidth of the bandpass filter is adjusted so that the input signal fits within the adjusted filtering bandwidth. A signal transmission and reception method characterized by the following:

2. This is a signal transmission and reception method in which an analog input signal is converted into a digital signal using an analog-to-digital converter, unwanted signals contained in the input signal and digital signal are reduced, and then the signal is converted back into an analog signal using a digital-to-analog converter and output. The amplitude of the input signal is amplified or attenuated by an amplitude control device according to the adjustment value of the amplitude control device to keep it within the dynamic range of the analog-to-digital converter. The power of the input signal after amplitude control is detected, and the control amplitude of the amplitude control device is adjusted so that the detected power is the same as the reference power, thereby keeping the amplitude of the input signal within the adjusted control amplitude. A signal transmission and reception method characterized by the following:

3. In the signal transmission and reception method according to claim 1 or claim 2, If the input signal contains multiple desired waves, the digital signal is separated into desired waves of different frequencies, the amplitude of each separated desired wave is analyzed, and based on the analysis results, the amplitude range of the multi-wave amplitude control device is adjusted so that unwanted waves contained in each desired wave are reduced. The digital signal is then input to the adjusted multi-wave amplitude control device so that unwanted waves contained in each desired wave are reduced. A signal transmission and reception method characterized by the following:

4. This is a signal transmission and reception method in which an analog input signal is converted into a digital signal using an analog-to-digital converter, unwanted signals contained in the input signal and digital signal are reduced, and then the signal is converted back into an analog signal using a digital-to-analog converter and output. The frequency bandwidth of the input signal is contained within the sampling frequency bandwidth of the analog-to-digital converter by a bandpass filter, the total power is contained within the receiving range of the analog-to-digital converter to reduce unwanted waves, the frequency of the digital signal is analyzed, the filtering bandwidth of the bandpass filter is adjusted based on the analysis results to contain the input signal within the adjusted filtering bandwidth, the amplitude of the input signal is contained within the dynamic range of the analog-to-digital converter by an amplitude control device to reduce unwanted waves, and the control amplitude of the amplitude control device is adjusted based on the power of the input signal after amplitude control to contain the amplitude of the input signal within the adjusted amplitude. A signal transmission and reception method characterized by the following:

5. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The input side of the analog-to-digital converter has a bandpass filter, the output side of the analog-to-digital converter has an equalizer, and the output side of the equalizer has a digital-to-analog converter. The bandpass filter reduces unwanted signals included in the input signal that are within the sampling frequency band of the analog-to-digital converter, thereby keeping the total power within the receiving range and allowing adjustment of the filtering bandwidth. The equalizer has the function of restoring the frequency characteristics of the desired band, which have been degraded by the bandpass filter, back to their original characteristics. The control system includes a frequency analyzer on the output side of the analog-to-digital converter in the transmission system, and a peak power detection device on the output side of the frequency analyzer. The frequency analyzer can analyze the frequency of the output signal from the analog-to-digital converter, and the peak power detection device can detect the peak power of unwanted waves present in either the unwanted or required band from the output of the frequency analyzer. Based on the output from the peak power detection device, the filtering bandwidth of the bandpass filter is adjusted to restore the frequency characteristics of the equalizer to their original characteristics. A signal transmission and reception device characterized by the following features.

6. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The analog-to-digital converter has an amplitude control device on its input side, a desired wave separation filter on its output side, a multi-wave amplitude control device on the output side of the desired wave separation filter, and a digital-to-analog converter on the output side of the multi-wave amplitude control device. The control system includes an analog power detection device on the input side of the analog-to-digital converter of the transmission system, which can adjust the amplitude value of the amplitude control device based on the output of the analog power detection device; a multi-wave input power detection device on the output side of the desired wave separation filter, which is also the input side of the multi-wave amplitude control device; and a multi-wave power detection device on the output side of the multi-wave amplitude control device, which can adjust the amplitude value of the multi-wave amplitude control device based on the outputs of the multi-wave input power detection device and the multi-wave power detection device. A signal transmission and reception device characterized by the following features.

7. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The analog-to-digital converter has an amplitude control device on its input side, a desired wave separation filter on its output side, a multi-wave amplitude control device on the output side of the desired wave separation filter, and a digital-to-analog converter on the output side of the multi-wave amplitude control device. The control system has an input power detection device on the input side of the amplitude control device of the transmission system, and an analog power detection device on the output side of the amplitude control device, which is also the input side of the analog-to-digital converter. The amplitude value of the amplitude control device can be adjusted based on the outputs of the input power detection device and the analog power detection device. The output side of the desired wave separation filter, which is also the input side of the multi-wave amplitude control device, has a multi-wave input power detection device. The multi-wave power detection device is also on the output side of the multi-wave amplitude control device. The amplitude value of the multi-wave amplitude control device can be adjusted based on the outputs of the multi-wave input power detection device and the multi-wave power detection device. A signal transmission and reception device characterized by the following features.

8. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The analog-to-digital converter has an amplitude control device on its input side, a desired wave separation filter on its output side, a multi-wave amplitude control device on the output side of the desired wave separation filter, and a digital-to-analog converter on the output side of the multi-wave amplitude control device. The control system includes a digital power detection device on the output side of the analog-to-digital converter of the transmission system, which can adjust the amplitude value of the amplitude control device based on the output of the digital power detection device; a multi-wave input power detection device on the output side of the desired wave separation filter and the input side of the multi-wave amplitude control device; a multi-wave power detection device on the output side of the multi-wave amplitude control device; and the amplitude value of the multi-wave amplitude control device can adjust based on the outputs of the multi-wave input power detection device and the multi-wave power detection device. A signal transmission and reception device characterized by the following features.

9. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes a digital-to-analog converter and an analog-to-digital converter. An amplitude control device is located at the input side of the analog-to-digital converter. A desired wave separation filter is located at the output side of the analog-to-digital converter to separate the desired wave. A multi-wave amplitude control device is located at the output side of the desired wave separation filter. A digital-to-analog converter is located at the output side of the multi-wave amplitude control device. The control system includes an input power detection device on the input side of the amplitude control device of the transmission system, a digital power detection device on the output side of the analog-to-digital converter and on the input side of the desired wave separation filter, and the amplitude value of the amplitude control device can be adjusted based on the outputs of the input power detection device and the digital power detection device. Furthermore, a multi-wave input power detection device is located on the output side of the desired wave separation filter and on the input side of the multi-wave amplitude control device, and a multi-wave power detection device is located on the output side of the multi-wave amplitude control device, and the amplitude value of the multi-wave amplitude control device can be adjusted based on the outputs of the multi-wave input power detection device and the multi-wave power detection device. A signal transmission and reception device characterized by the following features.

10. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The input side of the analog-to-digital converter has a bandpass filter and an amplitude control device. The output side of the analog-to-digital converter has a desired wave separation filter to separate the desired wave. The output side of the desired wave separation filter has a multi-wave amplitude control device, and the output side of the multi-wave amplitude control device has a digital-to-analog converter. The control system includes a frequency analyzer on the output side of the analog-to-digital converter of the transmission system and on the input side of the desired wave separation device, a multi-wave peak power detection device on the output side of the frequency analyzer, the frequency analyzer capable of analyzing the frequency of the output signal from the analog-to-digital converter, the multi-wave peak power detection device capable of detecting the peak power of unwanted waves present in either the unwanted or required band from the output of the frequency analyzer, and the ability to adjust the filtering bandwidth of the bandpass filter and control the amplitude of the amplitude control device based on the output from the multi-wave peak power detection device. A signal transmission and reception device characterized by the following features.

11. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The input side of the analog-to-digital converter has a bandpass filter and an amplitude control device. The output side of the analog-to-digital converter has a desired wave separation filter to separate the desired wave. The output side of the desired wave separation filter has a multi-wave equalizer. The output side of the multi-wave equalizer has a multi-wave amplitude control device. The output side of the multi-wave amplitude control device has a digital-to-analog converter. The control system includes an input power detection device on the input side of the transmission system's bandpass filter, a frequency analyzer on the output side of the analog-to-digital converter and the input side of the desired wave separation filter, and a multi-wave peak power detection device on the output side of the frequency analyzer. The frequency analyzer can analyze the frequency of the output signal from the analog-to-digital converter, and the multi-wave peak power detection device can detect the peak power of unwanted waves present in the unwanted or required band from the output of the frequency analyzer. Based on the output from the input power detection device, the amplitude of the amplitude control device is controlled, and based on the output from the multi-wave peak power detection device, the filtering bandwidth of the bandpass filter and the characteristics of the desired band of the multi-wave equalizer can be restored to their original characteristics. A signal transmission and reception device characterized by the following features.

12. A signal transceiver comprising an analog-to-digital converter that converts an analog input signal into a digital signal, and a digital-to-analog converter that reduces unwanted signals before converting the digital signal back into an analog signal for output, wherein the signal transceiver comprises a transmission system for transmitting input signals and a control system for reducing unwanted signals contained in the signals transmitted by the transmission system. The transmission system includes an analog-to-digital converter and a digital-to-analog converter. The input side of the analog-to-digital converter has a bandpass filter and an amplitude control device. The output side of the analog-to-digital converter has an equalizer. The output side of the equalizer has a signal processing unit. The output side of the signal processing unit has a digital-to-analog converter. The bandpass filter reduces unwanted signals contained in the input signal that are within the sampling frequency band of the analog-to-digital converter, thereby keeping the total power within the receiving range and allowing adjustment of the filtering bandwidth. The amplitude control device reduces unwanted signals by keeping the input signal within the dynamic range of the analog-to-digital converter. The equalizer has the function of restoring the frequency characteristics of the desired band, which have been degraded by the bandpass filter, back to their original characteristics. The control system includes a frequency analyzer and a digital power detection device on the output side of the analog-to-digital converter of the transmission system. A peak power detection device is located on the output side of the frequency analyzer. The frequency analyzer can analyze the frequency of the output signal from the analog-to-digital converter. The peak power detection device can detect the peak power of unwanted waves present in either the unwanted or required band from the output of the frequency analyzer. Based on the output from the peak power detection device, the filtering bandwidth of the bandpass filter can be adjusted, restoring the frequency characteristics of the equalizer to their original characteristics. A digital control device is located on the output side of the digital power detection device. A power signal converter is located on the output side of the digital control device. The output from the power signal converter can adjust the amplitude control range of the amplitude control device so that it fits within the dynamic range of the digital-to-analog converter. A signal transmission and reception device characterized by the following features.

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