Same-pilot frequency digital transfer station

Abstract

The invention provides a same and different frequency digital transfer station, which comprises a receiving link and a transmitting link, the receiving link comprises an antenna matching network, a first electric tuning filter, a low noise amplifier, a second electric tuning filter, a frequency mixer, an intermediate frequency amplifier, an intermediate frequency demodulation chip and a baseband chip which are connected in sequence; the transmitting link comprises a baseband chip, a control chip, a crystal oscillator, a phase-locked loop for transmitting, a transmitting VCO, a pre-amplifier, an attenuator, a pre-stage amplifier, a driving-stage amplifier, an exciting-stage amplifier and an antenna matching network which are connected in sequence; the crystal oscillator is further connected with the receiving phase-locked loop, the receiving phase-locked loop is connected with the receiving VCO, and the receiving VCO is connected with the frequency mixer. According to the invention, independent oscillation and phase-locked loops are adopted for receiving and transmitting, and the receiving VCO and the transmitting VCO lock corresponding working frequencies all the time when being started, so that the technical requirements of same-frequency transfer and different-frequency transfer are met.

Description

Technical Field

[0001] The present invention relates to the technical field of repeater stations, and in particular to a same-frequency and different-frequency digital repeater station. Background Art

[0002] The same-frequency repeater uses TDMA time division multiple access technology to achieve time division duplex same-frequency relay, which can save half of the frequency resources of the different-frequency repeater. Its equipment is integrated and the system is minimized. Only one frequency point is needed to realize the signal relay function, and communication deployment can be completed without a duplexer.

[0003] The heterodyne repeater uses frequency division full-duplex technology to achieve the purpose of simultaneous TDMA dual-time slot relay. The equipment is generally large in size and difficult to deploy. When using dual antennas, the isolation between the horizontal polarization and vertical polarization of the receiving / transmitting antennas must be considered, otherwise the relay equipment is easily damaged or the relay effect is not ideal; when using duplexers, the equipment needs to be customized according to the actual application frequency, which is costly and difficult to mass produce and sell. The equipment installation requires professional technicians to carry out the construction, and it is impossible to realize mobile temporary networking applications. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies of the prior art, an object of the present invention is to provide a same-frequency and different-frequency digital repeater to overcome the defects in the prior art.

[0005] In order to achieve the above-mentioned object, the present invention provides a same-frequency and different-frequency digital repeater, which includes a receiving link and a transmitting link; wherein:

[0006] The receiving link is composed of an antenna matching network, a first electrically tuned filter, a low-noise amplifier, a second electrically tuned filter, a mixer, an intermediate frequency filter, an intermediate frequency amplifier, an intermediate frequency demodulation chip and a baseband chip connected in sequence; wherein, the electromagnetic waves transmitted in space received by the antenna are filtered out through the antenna matching network to filter out high-frequency interference signals, so that only carriers below the target frequency band are received and pass through the first electrically tuned filter; the first electrically tuned filter preselects the carrier of the device operating frequency, the low-noise amplifier amplifies the preselected carrier, and the second electrically tuned filter filters the signal amplified by the low-noise amplifier again, filters out the intermodulation signals and out-of-band useless signals generated by the low-noise amplifier, and then provides them to the mixer; The mixer performs difference frequency and sum frequency on the carrier signal F0 and the local oscillator signal LO to generate intermediate frequencies IF=F0-LO and IF=F0+LO, and filters out the target intermediate frequency signal through the intermediate frequency filter to suppress the out-of-band intermediate frequency interference and then enter the intermediate frequency amplifier; the intermediate frequency amplifier performs level compensation on the intermediate frequency signal selected by the intermediate frequency filter; the intermediate frequency demodulation chip performs secondary mixing on the intermediate frequency signal and the local oscillator signal 2LO of the intermediate frequency demodulation chip, and the obtained 450KHz signal is filtered and demodulated by the frequency detector integrated in the intermediate frequency demodulation chip to obtain the modulated 4FSK signal; the baseband chip decodes the demodulated 4FSK signal, performs CRC check, and performs signal encoding to prepare for re-modulation and transmission;

[0007] The transmitting link is composed of a baseband chip, a control chip, a crystal oscillator, a transmitting phase-locked loop, a transmitting VCO, a preamplifier, an attenuator, a preamplifier, a driver amplifier, an excitation amplifier and an antenna matching network connected in sequence; wherein, when the receiving link receives a standard DMR signal and the baseband chip successfully demodulates the signal, the control chip controls the crystal oscillator and the transmitting phase-locked loop to start the transmitting VCO to lock the signal setting frequency, and the baseband chip modulates the transmitting VCO with a 4FSK data signal; the voltage control foot of the transmitting VCO reference crystal oscillator modulates the 4FSK data signal and performs VOC oscillation modulation to generate a carrier signal output to the preamplifier, the preamplifier preamplifies the carrier signal modulated by the transmitting VCO, the attenuator performs power control on the carrier signal modulated by the transmitting VCO, the preamplifier, the driver amplifier and the excitation amplifier amplify the modulated carrier signal to the target power, the carrier signal amplified by the excitation amplifier passes through the antenna matching network to filter out the harmonic signal, and the carrier signal is matched with the antenna and radiated into space by the antenna;

[0008] The crystal oscillator is connected to a receiving phase-locked loop, the receiving phase-locked loop is connected to a receiving VCO, the receiving VCO is connected to a mixer of a receiving link, and the control chip is used to control the crystal oscillator and the receiving phase-locked loop to start the receiving VCO to lock the operating frequency when the power is turned on, provide a local oscillator signal for the mixer, and control the crystal oscillator and the transmitting phase-locked loop to start the transmitting VCO to lock the operating frequency.

[0009] Through the above technical solution, the receiving phase-locked loop and the transmitting phase-locked loop are connected through a crystal oscillator, the receiving phase-locked loop is connected to the receiving VCO, and the transmitting phase-locked loop is connected to the transmitting VCO, so that both the receiving and transmitting adopt independent oscillation and phase-locked loop control circuit design, the receiving VCO and the transmitting VCO are always locked to the corresponding operating frequency when they are turned on, and there is no need to consider the loss or failure of the transfer data caused by the VCO locking not being fast or stable enough when switching time slots.

[0010] As a further explanation of the same-frequency and different-frequency digital repeater described in the present invention, preferably, the same-frequency and different-frequency digital repeater also includes a power control system, which includes a mean detector coupled to the microstrip type of the excitation stage of the transmitter link, the mean detector is connected to the APC controller, the mean detector detects the carrier signal amplified by the excitation stage, and amplifies the level of the carrier signal and sends it to the APC controller; the APC controller is respectively connected to the attenuator and control chip of the transmitter link, the APC controller compares the level of the amplified carrier signal with the reference level, and controls the attenuator of the transmitter link; the mean detector, the APC controller and the attenuator repeatedly detect, compare and attenuate in a continuous cycle to achieve transmission power control of the transmitter link.

[0011] Through the above technical solution, directional coupling detection and mean detection are adopted, and the detection-comparison-attenuation are repeated in a continuous cycle to achieve stable transmission of carrier power.

[0012] As a further description of the same-frequency and different-frequency digital repeater of the present invention, preferably, the receiving VCO provides a 0-10 dBm local oscillator signal to the mixer.

[0013] Through the above technical solution, the receiving VCO provides a 0-10dBm local oscillator signal to the mixer, ensuring that the local oscillator signal can effectively perform difference frequency or sum frequency with the carrier signal in the mixer.

[0014] As a further illustration of the same-frequency and different-frequency digital repeater of the present invention, preferably, the attenuator provides 0-30dB / 1dB step power control for the carrier signal modulated by the transmitting VCO.

[0015] Through the above technical solution, the attenuator provides 0-30dB / 1dB step power control for the transmitting VCO, ensuring the correct transmission and reliability of the carrier signal in the communication system.

[0016] As a further description of the same-frequency and different-frequency digital repeater of the present invention, preferably, the receiving link performs 30mS data reception through one time slot, and the transmitting link performs 30mS digital transmission through another time slot to achieve relaying.

[0017] Through the above technical solution, the receiving link and the transmitting link adopt TDMA time division duplex technology to realize the transfer, which can minimize the system of the transfer equipment, with small size, easy installation, affordable transfer cost and mobile signal coverage.

[0018] As a further description of the same-frequency and different-frequency digital repeater of the present invention, preferably, the receiving link and the transmitting link operate in a same-frequency repeater mode or a different-frequency repeater mode.

[0019] Through the above technical solution, the receiving link and the transmitting link adopt a dual VCO independent design, which can meet the technical requirements of the same-frequency transfer mode and the different-frequency transfer mode.

[0020] The beneficial effects of the present invention are as follows: the present invention connects a receiving phase-locked loop and a transmitting phase-locked loop through a crystal oscillator, the receiving phase-locked loop is connected to a receiving VCO, and the transmitting phase-locked loop is connected to a transmitting VCO, so that both receiving and transmitting adopt independent oscillation and phase-locked loop control circuit design, the receiving VCO and the transmitting VCO are always locked to the corresponding working frequency when they are turned on, and there is no need to consider that the VCO is not locked fast enough or stable enough to cause the transfer data to be lost or failed during time slot switching, and the technical requirements of receiving / transmitting same-frequency transfer and receiving / transmitting different-frequency transfer are met, and the activation is simple, and the same / different-frequency transfer can be realized by only the system's own antenna, and there is no need to consider the isolation between the horizontal polarization and the vertical polarization of the receiving / transmitting antenna, and there is no need to use a duplexer to achieve isolation, and there is no need for professional technicians to set up, and the equipment can be placed in an appropriate position at any time according to the call needs to increase the signal coverage of a large area of ​​the application site. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the same-frequency and different-frequency digital repeater of the present invention. DETAILED DESCRIPTION

[0022] In order to further understand the structure, features and other purposes of the present invention, the preferred embodiments are described in detail with reference to the accompanying drawings as follows. The embodiments described in the drawings are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention.

[0023] In a first embodiment of the present invention, Figure 1 As shown, the present invention provides a same-frequency and different-frequency digital repeater, and the same-frequency and different-frequency digital repeater includes a receiving link 1 and a transmitting link 2.

[0024] The receiving chain 1 includes an antenna matching network 11, a first electrically tunable filter 12, a low noise amplifier 13, a second electrically tunable filter 14, a mixer 15, an intermediate frequency filter 111, an intermediate frequency amplifier 16, an intermediate frequency demodulation chip 17 and a baseband chip 18 connected in sequence.

[0025] The electromagnetic waves transmitted in space received by the antenna are filtered out of high-frequency interference signals through the antenna matching network 11, and only the carrier below the target frequency band is allowed to pass. The first electrically tuned filter 12 preselects the carrier of the device operating frequency. The low noise amplifier 13 amplifies the preselected carrier. The second electrically tuned filter 14 filters the signal amplified by the low noise amplifier 13 again, filters out the intermodulation signal and out-of-band useless signal generated by the low noise amplifier 13 and provides them to the mixer 15. The mixer 15 performs difference frequency and sum frequency on the carrier signal F0 and the local oscillator signal LO to generate the intermediate frequency F0-LO=IF and F0+LO=IF. Any two signals will generate two frequencies, the difference frequency and the sum frequency, through the mixer 15. There are many electromagnetic waves transmitted in space, and some are received by the antenna and enter the mixer, and some unnecessary intermediate frequency signals will be generated when they are output. The intermediate frequency filter 111 filters out the target intermediate frequency signal and suppresses the out-of-band intermediate frequency interference. The intermediate frequency amplifier 16 performs level compensation on the intermediate frequency signal selected by the intermediate frequency filter 111. The IF demodulation chip 17 performs secondary mixing on the IF signal and the local oscillator signal 2LO of the IF demodulation chip 17 to obtain a 450KHz signal, which is then filtered and demodulated by the frequency detector integrated in the IF demodulation chip 17 to obtain the modulated 4FSK signal. The local oscillator signal 2LO of the IF demodulation chip 17 is twice the frequency of the VOC reference crystal oscillator and enters the IF demodulation chip 17. The baseband chip 18 decodes, performs CRC check, and performs signal encoding on the demodulated 4FSK signal to prepare for re-modulation and transmission.

[0026] The transmission chain 2 includes a baseband chip 18, a control chip 3, a crystal oscillator 21, a transmission phase-locked loop 22, a transmission VCO 23, a preamplifier 24, an attenuator 25, a pre-amplifier 26, a driver amplifier 27, an excitation amplifier 28 and an antenna matching network 11 connected in sequence.

[0027] The receiving link 1 receives the standard DMR signal. When the baseband chip 18 successfully demodulates the signal, the control chip 3 starts the transmitting VCO23 to work and locks the signal setting frequency. The baseband chip 18 modulates the transmitting VCO23 with a 4FSK data signal. There are two main modulation signals for VCO signal debugging. One is the voltage control foot of the reference crystal oscillator modulating the 4FSK signal; the other is the VCO oscillation modulation, collectively referred to as VCO modulation. The preamplifier 24 preamplifies the carrier signal modulated by the transmitting VCO23. The attenuator 25 realizes high-precision power control for the transmitting power of the carrier signal modulated by the transmitting VCO23. Preferably, the attenuator 25 provides 0-30dB / 1dB step power control for the carrier signal modulated by the transmitting VCO23. The preamplifier 26, the driving amplifier 27 and the excitation amplifier 28 amplify the carrier signal modulated by the transmitting VCO23 to the target power. The carrier signal amplified by the excitation amplifier 28 is radiated into space by the antenna after filtering out the harmonic signal and matching the antenna through the antenna matching network 11.

[0028] The crystal oscillator 21 is connected to the receiving phase-locked loop 19, the receiving phase-locked loop 19 is connected to the receiving VCO 110, and the receiving VCO 110 is connected to the mixer 15 of the receiving link 1. When the control chip 3 is turned on, the control crystal oscillator 21 and the receiving phase-locked loop 19 start the receiving VCO 110 to lock the working frequency, provide the local oscillator signal to the mixer 15, and control the crystal oscillator 21 and the transmitting phase-locked loop 22 to start the transmitting VCO 23 to lock the working frequency. Among them, the working frequency is the local oscillator frequency (LO) = the channel receiving frequency (F0) - the intermediate frequency (IF). Preferably, the receiving VCO 110 provides the mixer 15 with a 0-10dBm local oscillator signal.

[0029] In this embodiment, both receiving and transmitting use independent oscillation and phase-locked loop control circuit design, and the receiving VCO and transmitting VCO are always locked to the corresponding working frequency when they are turned on. Since the VCO is always in a locked state, there is no need to consider the loss or failure of the transfer data caused by the VCO locking not being fast enough or stable enough when switching time slots, which meets the technical requirements of receiving / transmitting same-frequency transfer and receiving / transmitting different-frequency transfer; and it is simple to enable, only the system needs to have its own antenna to achieve the same / different-frequency transfer, and there is no need to consider the isolation between the horizontal polarization and vertical polarization of the receiving / transmitting antenna, no need to use a duplexer to achieve isolation, and no need for professional technicians to set up. The equipment can be placed in an appropriate position at any time according to the call needs to increase the signal coverage of a large area of ​​the application site.

[0030] In a second embodiment of the present invention, Figure 1 As shown, the same-frequency and different-frequency digital repeater also includes a power control system, which includes a mean detector 4 connected to the excitation stage 28 of the transmitter link 2 through a microstrip coupling. The mean detector 4 is connected to the APC controller 5, and the APC controller 5 is connected to the attenuator 25 and the control chip 3 of the transmitter link 2 respectively.

[0031] The mean detector 4, APC controller 5 and attenuator 25 constitute a power control system. The mean detector 4 detects the carrier signal amplified by the excitation stage 28, and amplifies the level of the carrier signal and sends it to the APC controller 5. The APC controller 5 compares the level of the amplified carrier signal with the reference level and controls the attenuator 25 of the transmitter chain 2. The mean detector 4, APC controller 5 and attenuator 25 realize the transmission power control of the transmitter chain 2 by repeatedly performing detection, comparison and attenuation in a continuous cycle.

[0032] In this implementation, directional coupling detection and mean value detection are adopted, and detection-comparison-attenuation are repeated in a continuous cycle to achieve stable transmission of carrier power.

[0033] In the third embodiment of the present invention, since the first embodiment adopts a dual VCO independent design and the operating frequency is always locked when powered on, preferably, the receiving chain 1 and the transmitting chain 2 can operate in the same frequency transfer mode or the different frequency transfer mode.

[0034] In the fourth embodiment of the present invention, the receiving link 1 and the transmitting link 2 both use TDMA time division multiple access technology when performing the same frequency transfer or different frequency transfer, for example, receiving in time slot 1, baseband decoding, CRC check and data encoding, and then using time slot 2 to send data; or receiving in time slot 2, baseband decoding, CRC check and data encoding, and then using the next time slot 1 to send data. Preferably, the receiving link 1 receives data through a time slot 30mS, and the transmitting link 2 realizes the transfer through another time slot 30mS digital transmission.

[0035] In this embodiment, TDMA time division multiple access technology is used to minimize the system of the transfer equipment, with advantages such as small size, easy installation and deployment, affordable transfer cost and mobile signal coverage.

[0036] It should be noted that the above invention content and specific implementation methods are intended to demonstrate the practical application of the technical solution provided by the present invention and should not be interpreted as limiting the scope of protection of the present invention. Those skilled in the art can make various modifications, equivalent substitutions or improvements within the spirit and principles of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A same-frequency and different-frequency digital repeater, characterized in that: The same-frequency and different-frequency digital repeater comprises a receiving link (1) and a transmitting link (2); wherein: The receiving chain (1) is composed of an antenna matching network (11), a first electrically tunable filter (12), a low noise amplifier (13), a second electrically tunable filter (14), a mixer (15), an intermediate frequency filter (111), an intermediate frequency amplifier (16), an intermediate frequency demodulation chip (17) and a baseband chip (18) which are connected in sequence; wherein: The electromagnetic waves transmitted in space are received by the antenna and filtered out high-frequency interference signals through the antenna matching network (11), so that only carrier waves below the target frequency band are received and passed through the first electrically tuned filter (12); the first electrically tuned filter (12) pre-selects a carrier wave of the device operating frequency, the low noise amplifier (13) amplifies the pre-selected carrier wave, the second electrically tuned filter (14) filters the signal amplified by the low noise amplifier (13) again, filters out the intermodulation signal and out-of-band useless signal generated by the low noise amplifier (13), and then provides the signal to the mixer (15); the mixer (15) performs difference frequency and sum frequency on the carrier signal F0 and the local oscillator signal LO to generate an intermediate frequency IF=F0-L O and IF = F0 + LO, and the target intermediate frequency signal is filtered out by the intermediate frequency filter (111) to suppress the out-of-band intermediate frequency interference and then enter the intermediate frequency amplifier (16); the intermediate frequency amplifier (16) performs level compensation on the intermediate frequency signal selected by the intermediate frequency filter (111); the intermediate frequency demodulation chip (17) performs secondary mixing on the intermediate frequency signal and the local oscillator signal 2LO of the intermediate frequency demodulation chip (17), and the obtained 450KHz signal is filtered and demodulated by the discriminator integrated in the intermediate frequency demodulation chip (17) to obtain the modulated 4FSK signal; the baseband chip (18) decodes the demodulated 4FSK signal, performs CRC check, and performs signal encoding to prepare for re-modulation and transmission; The transmission link (2) is composed of a baseband chip (18), a control chip (3), a crystal oscillator (21), a transmission phase-locked loop (22), a transmission VCO (23), a preamplifier (24), an attenuator (25), a pre-amplifier (26), a driver amplifier (27), an excitation amplifier (28) and an antenna matching network (11) which are connected in sequence; wherein, When the receiving link (1) receives a standard DMR signal and the baseband chip (18) successfully demodulates the signal, the control chip (3) controls the crystal oscillator (21) and the transmitting phase-locked loop (22) to start the transmitting VCO (23) to lock the signal setting frequency, and the baseband chip (18) modulates the transmitting VCO (23) with a 4FSK data signal; the transmitting VCO (23) modulates the 4FSK data signal with reference to the voltage control pin of the crystal oscillator (21) and performs VOC oscillation modulation to generate a carrier signal output to the preamplifier (24); the preamplifier (24) preamplifies the carrier signal modulated by the transmitting VCO (23); the attenuator (25) performs power control on the carrier signal modulated by the transmitting VCO (23); the preamplifier (26), the driving amplifier (27) and the excitation amplifier (28) amplify the modulated carrier signal to the target power; the carrier signal amplified by the excitation amplifier (28) passes through the antenna matching network (11) to filter out the harmonic signal, and the carrier signal is matched with the antenna and radiated into space by the antenna; The crystal oscillator (21) is connected to a receiving phase-locked loop (19), the receiving phase-locked loop (19) is connected to a receiving VCO (110), the receiving VCO (110) is connected to a mixer (15) of a receiving link (1), and the control chip (3) is used to control the crystal oscillator (21) and the receiving phase-locked loop (19) to start the receiving VCO (110) to lock the working frequency, provide a local oscillator signal to the mixer (15), and control the crystal oscillator (21) and the transmitting phase-locked loop (22) to start the transmitting VCO (23) to lock the working frequency.

2. The same frequency and different frequency digital repeater according to claim 1, characterized in that: The same-frequency and different-frequency digital repeater also includes a power control system, which includes a mean value detector (4) coupled with a microstrip type excitation stage (28) of a transmitter link (2), the mean value detector (4) being connected to an APC controller (5), the mean value detector (4) detecting the carrier signal amplified by the excitation stage (28), and amplifying the level of the carrier signal and sending it to the APC controller (5); the APC controller (5) being connected to an attenuator (25) and a control chip (3) of the transmitter link (2), respectively, the APC controller (5) comparing the level of the amplified carrier signal with a reference level, and controlling the attenuator (25) of the transmitter link (2); the mean value detector (4), the APC controller (5) and the attenuator (25) repeatedly detect, compare and attenuate in a continuous cycle to realize transmission power control of the transmitter link (2).

3. The same frequency and different frequency digital repeater according to claim 1, characterized in that: The receiving VCO (110) provides a 0-10 dBm local oscillation signal to the mixer (15).

4. The same frequency and different frequency digital repeater according to claim 1, characterized in that: The attenuator (25) provides 0-30dB / 1dB step power control for the carrier signal modulated by the transmit VCO (23).

5. The same frequency and different frequency digital repeater according to claim 1, characterized in that: The receiving link (1) performs 30mS data reception through one time slot, and the transmitting link (2) performs 30mS digital transmission through another time slot to achieve transfer.

6. The same frequency and different frequency digital repeater as claimed in claim 1, characterized in that: The receiving link (1) and the transmitting link (2) operate in a same-frequency transfer mode or a different-frequency transfer mode.

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