Amplitude modulation broadcast co-frequency suppression device
By using an amplitude modulation broadcast co-frequency suppression device, which utilizes an RF sampling module and an RF signal generator for frequency and phase control, the high cost and complexity of medium wave broadcast co-frequency signal suppression are solved, achieving efficient and low-cost signal suppression.
Patent Information
- Application Number
- CN202520242512.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-14
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2035-02-14
AI Technical Summary
Existing technologies for suppressing co-channel signals in medium-wave broadcasting suffer from high costs and technical complexity. Existing methods, such as increasing transmission power or using phase-locked loop technology, are also characterized by high costs, high complexity, and poor suppression effects.
An amplitude modulation broadcast co-frequency suppression device is adopted. Through an RF sampling module, a host computer, and an RF signal generator, the frequency and phase of the RF signal are precisely controlled. By using an adjustable phase exciter and PLL frequency synthesis and stabilization phase-locked loop technology, fast and accurate phase changes are achieved, thus realizing efficient suppression of co-frequency signals.
It reduces the operation and maintenance costs and complexity of the transmission system, improves signal coverage, reduces reliance on high-power transmission equipment, improves signal accuracy and communication quality, and reduces energy consumption.
Smart Images
Figure CN223652284U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of co-frequency suppression technology, specifically relating to an amplitude modulation broadcast co-frequency suppression device. Background Technology
[0002] In the field of medium wave broadcasting, achieving local coverage while avoiding interference from signals from distant locations has always been a technical challenge. The signal propagation characteristics of medium wave broadcasting make it susceptible to interference from signals on the same or adjacent frequencies from other locations when providing local coverage. To suppress this interference, traditional technical means usually rely on increasing the transmission power, that is, suppressing the interference signal by increasing the field strength of the local signal. However, although this method is effective to a certain extent, it brings a significant increase in technical costs, including the dual burden of equipment costs and operation and maintenance costs.
[0003] In the existing technology, the co-frequency coverage suppression technology improves the signal coverage effect and reduces interference by increasing the local continuous transmission output power several times. Although this method can suppress the signal to a certain extent, its disadvantage is that it is costly. Because it requires a significant increase in transmission power, this not only increases the equipment investment of the radio station, but also increases the daily power consumption and maintenance costs.
[0004] The second existing technology uses the same-frequency phase-locked loop (PLL) coverage suppression technology. This technology uses a phase-locked loop (PLL) to lock onto the carrier of the signal transmitted from another location, ensuring that the local transmitted signal has the same frequency and opposite phase as the signal from another location at the receiving point. This causes the far-end signals to cancel each other out when superimposed, significantly reducing their signal-to-noise ratio. However, this method also has its shortcomings. First, due to the coherence zone limitation between the two transmission points, the same-frequency suppression effect is good in a certain area, but there will inevitably be areas with poor suppression effect outside half a wavelength, which leads to the emergence of suppression blind spots. Second, the signal phase-locking environment technology is highly complex and it is difficult to obtain a stable phase-locked signal output, which increases the difficulty and uncertainty of the technology implementation.
[0005] In summary, existing technologies for suppressing co-channel signals in medium-wave broadcasting suffer from drawbacks such as high cost and technical complexity, necessitating a new technical solution to address these issues. Utility Model Content
[0006] The purpose of this invention is to provide an amplitude modulation broadcast co-frequency suppression device that can achieve stable, reliable, precise and controllable output of a transmitter excitation source signal with variable phase during medium wave transmission. By precisely controlling the continuous cyclic change of phase, it can achieve efficient suppression of co-frequency signals for a portion of each time period. Through rapid and precise phase change control, it can suppress high-power signals by lower-power signals, thereby reducing the operation and maintenance costs and complexity of the transmission system.
[0007] The specific technical solution adopted by this utility model is as follows:
[0008] An amplitude modulation broadcast co-frequency suppression device includes: an RF sampling module, a host computer, and an RF signal generator;
[0009] The radio frequency sampling module is located in the antenna tuning network of the transmitting antenna. The collected air radio frequency signals are converted into frequency domain data and submitted to the host computer.
[0010] The host computer generates control signals based on the frequency and phase values in the collected frequency domain data;
[0011] The radio frequency signal generator receives the control signal output by the host computer, corrects the frequency and phase of its own output radio frequency signal, and finally outputs the corrected radio frequency signal.
[0012] The radio frequency sampling module, the host computer, and the radio frequency signal generator are connected via a communication line.
[0013] The radio frequency signal generator includes a temperature-controlled crystal oscillator circuit and a DDS digital processing circuit.
[0014] The thermostatic crystal oscillator circuit provides a clock signal to the DDS digital processing circuit and outputs a medium-wave radio frequency signal to the DDS digital processing circuit.
[0015] The DDS digital processing circuit generates a series of digital signals, which are then converted into analog signals by a digital-to-analog converter.
[0016] The radio frequency signal generator also includes a radio frequency amplifier unit. The radio frequency amplifier acquires the analog signal output by the DDS digital processing circuit, amplifies the intensity of the analog signal, and outputs the final radio frequency signal.
[0017] The radio frequency sampling module includes a radio frequency signal acquisition unit, an analog-to-digital conversion unit, and a signal processing unit;
[0018] The radio frequency signal acquisition unit acquires the air radio frequency signal;
[0019] The analog-to-digital converter unit is used to convert analog signals into digital signals;
[0020] The signal processing unit processes the digital signal and outputs the corresponding frequency domain data. Attached Figure Description
[0021] Figure 1 This is a block diagram of the carrier signal control system of this utility model;
[0022] Figure 2 This is a schematic diagram of the far-end co-frequency signal suppression in this utility model;
[0023] Figure 3 This utility model relates to a cyclic phase-shifting system for amplitude modulation excitation signals at the same frequency. Detailed Implementation
[0024] To make the objectives and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of this utility model and does not strictly limit the scope of protection specifically claimed by this utility model.
[0025] like Figure 1-3 As shown, an amplitude modulation broadcast co-frequency suppression device includes: an RF sampling module, a host computer, and an RF signal generator;
[0026] The radio frequency sampling module is located in the antenna tuning network of the transmitting antenna. It collects the air radio frequency signals, converts them into frequency domain data, and submits them to the host computer.
[0027] The host computer generates control signals based on the frequency and phase values in the acquired frequency domain data;
[0028] The radio frequency signal generator receives the control signal output from the host computer. The output frequency accuracy can reach 10-10. It completes the correction of the frequency and phase of its own output radio frequency signal and finally outputs the corrected radio frequency signal.
[0029] The RF sampling module, the host computer, and the RF signal generator are connected via a communication line, and the output of the RF signal generator is connected to the input of the RF transmitter excitation source.
[0030] The radio frequency signal generator includes a temperature-controlled crystal oscillator circuit and a DDS digital processing circuit;
[0031] The temperature-controlled crystal oscillator circuit provides a clock signal for the DDS digital processing circuit and outputs a medium-wave radio frequency signal with high stability and accuracy to the DDS digital processing circuit.
[0032] The DDS digital processing circuit generates a series of digital signals, which are then converted into analog signals by a digital-to-analog converter.
[0033] The radio frequency signal generator also includes a radio frequency amplifier unit. The radio frequency amplifier acquires the analog signal output by the DDS digital processing circuit, amplifies the intensity of the analog signal, and outputs the final radio frequency signal.
[0034] The radio frequency sampling module includes a radio frequency signal acquisition unit, an analog-to-digital conversion unit, and a signal processing unit;
[0035] Radio frequency signals acquired by the frequency signal acquisition unit;
[0036] The analog-to-digital converter (ADC) is used to convert analog signals into digital signals;
[0037] The signal processing unit processes digital signals and outputs corresponding frequency domain data.
[0038] See appendix Figure 2 The host computer sets a 3-second cycle, and the adjustable phase exciter adjusts the phase of the local carrier signal at 0.1-second intervals according to the host computer's settings. The phase adjustment is performed cyclically, that is, the local carrier signal phase is moved by 12 degrees in each cycle.
[0039] By cyclically adjusting the phase of the local carrier signal, at any receiving point, both the local medium-wave coverage signal and the remote signal have a half-cycle signal superposition and cancellation zone. When the local carrier signal and the remote carrier signal meet at the receiving point, due to their different phases, phase superposition (signal enhancement) will occur within half a cycle (1.5 seconds), while phase cancellation (signal weakening) will occur within the other half cycle (1.5 seconds).
[0040] By using this cyclic phase-shifting amplitude modulation co-frequency suppression technology, even if the local medium wave signal is transmitted at low power, it is possible to interrupt the propagation of the medium wave signal content at the same frequency in a different location. This not only improves the signal coverage effect but also reduces the dependence on high-power transmission equipment, thereby reducing technical costs and energy consumption.
[0041] This utility model's technical solution improves the efficiency of suppressing co-frequency signals during medium-wave coverage by introducing cyclic phase shifting technology for the same-frequency amplitude modulation excitation signal. Through rapid and precise phase change control, it achieves the suppression of high-power signals by lower-power signals, thereby reducing the operation and maintenance costs and complexity of the transmission system.
[0042] Based on this, the present application also has the following advantages:
[0043] By introducing an adjustable phase exciter and employing PLL frequency synthesis and stabilization phase-locked loop technology, this scheme enables independent adjustment of frequency and phase, thereby providing a stable phase output in the transmitter. This helps reduce signal distortion caused by phase drift, improving signal accuracy and communication quality.
[0044] This solution can achieve rapid phase change of co-frequency signals within a period of 3-6 seconds, which enables the system to respond quickly to different coverage requirements and improve the suppression effect of co-frequency signals.
[0045] Within a 3-6 second cycle, this solution can achieve partial inter-segment suppression of signals at the same frequency, which helps to reduce interference between signals and improve the system's anti-interference capability.
[0046] The adjustable phase exciter has signal retrieval and detection capabilities, and can automatically fine-tune and lock the phase difference of the output signal according to the phase shift. This automatic phase fine-tuning capability enables the system to adapt to phase shifts caused by environmental changes and equipment aging, thereby maintaining the phase consistency and accuracy of the signal;
[0047] Compared with traditional phase adjustment methods, this solution does not require complex hardware support, thereby reducing hardware costs and system complexity, making it easier to integrate into existing RF systems and improving the system's economy and practicality.
[0048] In summary, this invention provides a cyclic phase-shifting technique for amplitude modulation (AM) excitation signals at the same frequency. An adjustable phase exciter is introduced into the transmitter, employing a PLL (Programmable Logic Controller) for frequency synthesis and stable phase-locked looping. The frequency and phase are independently adjustable, enabling rapid changes in the phase relative to the AM carrier phase of the same-frequency signal. Within a 3-6 second cycle, it can suppress the same-frequency signal for a portion of the interval. The adjustable phase exciter has signal retrieval and detection capabilities, and can automatically fine-tune the phase difference of the locked output signal based on phase shift.
[0049] The above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. Structures, devices, and operating methods not specifically described or explained in this utility model, unless otherwise specified or limited, shall be implemented using conventional methods in the field.
Claims
1. An amplitude modulation broadcast co-frequency suppression device, characterized in that, include: RF sampling module, host computer, and RF signal generator; The radio frequency sampling module is located in the antenna tuning network of the transmitting antenna. The collected air radio frequency signals are converted into frequency domain data and submitted to the host computer. The host computer generates control signals based on the frequency and phase values in the collected frequency domain data; The radio frequency signal generator receives the control signal output by the host computer, corrects the frequency and phase of its own output radio frequency signal, and finally outputs the corrected radio frequency signal.
2. The amplitude modulation broadcast co-frequency suppression device according to claim 1, characterized in that: The radio frequency sampling module, the host computer, and the radio frequency signal generator are connected via a communication line.
3. The amplitude modulation broadcast co-frequency suppression device according to claim 1, characterized in that: The radio frequency signal generator includes a temperature-controlled crystal oscillator circuit and a DDS digital processing circuit. The thermostatic crystal oscillator circuit provides a clock signal to the DDS digital processing circuit and outputs a medium-wave radio frequency signal to the DDS digital processing circuit. The DDS digital processing circuit generates a series of digital signals, which are then converted into analog signals by a digital-to-analog converter.
4. The amplitude modulation broadcast co-frequency suppression device according to claim 3, characterized in that: The radio frequency signal generator also includes a radio frequency amplifier, which acquires the analog signal output by the DDS digital processing circuit, amplifies the intensity of the analog signal, and outputs the final radio frequency signal.
5. The amplitude modulation broadcast co-frequency suppression device according to claim 1, characterized in that: The radio frequency sampling module includes a radio frequency signal acquisition unit, an analog-to-digital conversion unit, and a signal processing unit; The radio frequency signal acquisition unit acquires the air radio frequency signals; The analog-to-digital converter unit is used to convert analog signals into digital signals; The signal processing unit processes the digital signal and outputs the corresponding frequency domain data.