JP2007116644A - General-purpose, highly efficient digital ssb radio equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio equipment in which efficiency in transmission of data signals is improved in a medium frequency band or higher. <P>SOLUTION: A carrier wave is modulated by a modulation wave composed of a reference signal in sinusoidal wave formed synchronously with the carrier wave and the data signal, and transmitted by a band limited SSB. On the receiving side, a local oscillation frequency and a local carrier frequency are generated on the basis of the cycle of the reference signal, and conversion and synchronizing detection are performed without a frequency error. Besides, the data signal is accurately decoded based on the level of the reference signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

Detailed Description of the Invention

  The present invention relates to an SSB radio used for a single sideband (SSB) communication system.

  The SSB wireless communication method is widely used as a method for performing wireless communication by performing amplitude modulation with a modulation signal.

  This SSB wireless communication method suppresses one of the carrier wave and the upper and lower sidebands and one of the upper and lower sidebands, and transmits only one of the upper and lower sidebands. It is. This method not only saves power but also halves the frequency band, and can take many communication channels.

  FIG. 5 is a diagram showing a block configuration of a receiving circuit of a radio used in a conventional SSB radio communication system. In FIG. 5, the antenna 101 receives a single sideband signal sent from the transmission side and amplifies it by the high frequency amplifier 103. In the mixing circuit 105, the single sideband signal from the high frequency amplifier 103 and the signal from the first local oscillation circuit 106 are mixed and converted into a first intermediate frequency signal through the bandpass filter circuit 107. The output of the band filter circuit 107 is input to the intermediate frequency amplifier circuit 108. Further, the output of the intermediate frequency amplification circuit 108 is input to the mixing circuit 109, mixed with the output of the second local oscillation circuit 110, and converted into a second intermediate frequency signal through the band-pass filtering circuit 111. The output of the band filtering circuit 111 is input to the intermediate frequency amplifier circuit 112, and the gain is automatically adjusted by the average value detection circuit 113 and the gain control circuit 114 so that the magnitude of the output becomes a predetermined value. In the synchronous detection circuit 115, the intermediate frequency signal whose gain has been automatically adjusted and the output of the local carrier wave oscillation circuit 116 are mixed and demodulated. The output signal of the synchronous detection circuit 115 is filtered by the low frequency filter 117 and further amplified by the low frequency amplifier 118 to obtain an output.

Problems to be solved by the invention

  In this SSB wireless communication system, there is no carrier signal to be used as a level adjustment reference in automatic gain adjustment in the average value detection circuit 113 and gain adjustment circuit 114 in the intermediate frequency amplifier 112 in FIG. It is necessary to set the constant sufficiently longer than the period of the modulation signal. For this reason, when the received signal level fluctuates in a cycle shorter than the time constant of automatic gain adjustment due to the condition of the radio communication path, amplitude distortion occurs in the receiving circuit, and the received output fluctuates.

  Further, in order to completely reproduce the waveform of the modulation signal, the frequency for matching the frequencies of the transmission side and the reception side is changed from the first local oscillator 106 to the mixing circuit 105, and from the second local oscillator 110 to the mixing circuit. 109, and from the local carrier oscillator 116 to the synchronous detection circuit 115, even if some errors are allowed, it is necessary to give a frequency within the allowable range. Therefore, in order to match the frequency on the transmission side with the frequency on the reception side, an ultra-high stability transmitter is required.

  In the SSB wireless communication system, the reception output level varies depending on the conditions of the wireless communication path, so that the amplitude value cannot be handled as a modulation value of digital data, and efficient data transfer cannot be performed.

  Therefore, the present inventors perform the automatic gain control of the receiving circuit immediately and highly accurately regardless of the conditions of the wireless communication path while taking advantage of the high power efficiency and narrow frequency band transmission in the SSB wireless communication system, In addition, an SSB wireless communication method and a wireless device that can generate a frequency synchronized with a transmission side frequency based on a received signal have already been proposed (Japanese Patent Application Nos. 2001-157471 and 2001-384205). Also in this proposal, the signal is limited to a digital signal, but at present, there is no problem because the voice can be easily digitized.

  It is an object of the present invention to provide an SSB radio capable of improving the proposed SSB radio communication system and radio, further improving the data signal transmission efficiency, and simplifying the circuit on the receiving side. And

Means to solve the problem

The SSB wireless device according to claim 1 is a sine wave-like reference signal having a constant amplitude and a width equal to that of the reference signal, which is formed to have a predetermined width and a predetermined period on the transmission side, and the amplitude of the reference signal is a reference. Using a data signal having an amplitude representing a binary or multi-value digital value as a modulation input, the carrier wave is modulated and transmitted in a single sideband,
On the receiving side, the reception gain is automatically adjusted based on the reference signal, and the amplitude value of the carrier wave of the reception signal is set immediately before or after the switching of each signal with the amplitude value of the reference signal being a peak value as a reference. An amplitude value at an appropriate location is measured, and the digital value is detected.

According to a second aspect of the present invention, there is provided a frequency generator that generates a local carrier wave and a local oscillation wave from a common oscillation source, and having a predetermined width, a predetermined cycle, and a constant amplitude based on the frequency generated by the frequency generator. A reference signal composed of a plurality of sine waves, and a sine wave data signal that expresses a binary or multi-value digital value having the same width, the same number of sine waves as the reference signal, and the amplitude of the reference signal Modulated wave generating means for generating a modulated wave;
Modulation means for amplitude-modulating the local carrier wave with the modulated wave;
Bandpass filter means for passing only the upper or lower single sideband of the modulation output of this modulation means;
A frequency conversion means for shifting the output of the band pass filter means by the local oscillation wave to be a transmission carrier signal;
On the receiving side, the single sideband communication signal is shifted by a local oscillation frequency signal and converted to an intermediate frequency signal, an intermediate frequency amplification means for amplifying the intermediate frequency signal from the frequency conversion means, and A frequency detecting means for outputting a frequency component of the period of the reference signal from the output of the intermediate frequency amplifying means;
Based on the frequency generating means for generating the local oscillation frequency signal based on the frequency component of the period of the reference signal from the frequency detection means, the local carrier oscillation circuit synchronized with the local oscillation frequency, and the output thereof A synchronous detection circuit for demodulating the received signal, and detecting the digital value of the signal from the amplitude value of the cycle immediately before the signal is switched in the demodulated output of each signal.

  According to the present invention, the advantages of high power efficiency and narrow frequency band transmission in the SSB wireless communication system can be further expanded, and the frequency utilization efficiency can be greatly improved.

  In addition, the modulation frequency is a single sine wave that is sufficiently higher than the audio frequency. If the frequency of the reference signal is increased and controlled so that the amplitude is constant, the amplitude distortion due to fading, noise, etc. In addition, it is possible to reduce the influence of the amplitude distortion that occurs when the received signal level fluctuates depending on the condition of the wireless communication path to a level that can be ignored.

  Further, the band-pass filters on the transmission side and the reception side are set so that the amplitude value of the carrier wave of the received reference signal and data signal is proportional to the amplitude value of the transmission side modulation signal at least immediately before the reference signal and the data signal are switched. By adjusting the bandwidth, it becomes possible to detect the digital value of the data signal from the amplitude value of the carrier wave without demodulation, and the complicated synchronous detection circuit can be eliminated, and the circuit can be further simplified.

  In addition, by detecting the digital value immediately before switching between the reference signal and the data signal that are closest to the amplitude value of the modulation signal on the transmission side, more data can be transmitted and the frequency utilization efficiency is further improved. it can.

  Further, since the local oscillation frequency and the local carrier frequency can be adjusted in synchronization with the period of the received reference signal, the synchronization can be almost completely achieved without requiring an ultra-high stability oscillator. Therefore, the demodulation efficiency is improved and the influence of noise and the like is reduced.

  From the above, by using the SSB radio of the present invention for all frequency bands above the medium wave band such as VHF band and UHF band, the frequency utilization efficiency of the frequency band above the medium wave band is greatly improved. it can.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of a transmitting side radio of the SSB radio communication system according to an embodiment of the present invention, and FIG. 2 is a diagram showing waveforms of respective parts of the radio.

  In this embodiment, in the case of transmitting a multi-value digital signal, when the modulation frequency is a single frequency sine wave (19.2 kHz in this embodiment) and frequency stability is required, Synchronize with local carrier. A signal is put on the amplitude value of one cycle or a plurality of cycles (4 cycles in this embodiment) of this modulated wave, a reference signal having a constant amplitude and a constant interval is provided in one of the signals, and a plurality of data signals are provided therebetween. (Three in this embodiment) are inserted to form a modulated wave. The local carrier wave is amplitude-modulated with this modulated wave, and one single sideband wave (upper side in this embodiment) is transmitted.

  In FIG. 1, a synthesizer circuit 11 synchronizesly generates various frequency signals necessary for the transmission side operation of the SSB wireless communication system of the present invention. However, when data detection is performed using a carrier wave, it is not necessary to synchronize.

  The band-pass filtering circuit 12 is supplied with a 19.2 kHz rectangular wave having a constant amplitude and a duty ratio of 50% from the synthesizer circuit 11 and outputs a sine modulation frequency signal to the band-pass filtering circuit 12. Input to the attenuation circuit 13. Since the resistance attenuating circuit 13 corresponds to the data signal D having m values (eight values in this embodiment), the resistance attenuating circuit 13 includes m resistance attenuators.

Each output from the resistance attenuation circuit 13 is input to the switching circuit 14. On the other hand, the control circuit 15 sends a switching signal corresponding to the digital data every 1 / f seconds (about 0.21 ms in the case of 4.8 kHz in this embodiment) of the modulation wave nf ₁ (in this embodiment 19. 2 kHz) and is input to the switching circuit 14 in synchronization with the zero cross. In the switching circuit 14, the reference signal K is set to zero attenuation, and the data signal D selects the output of the resistance attenuator designated by the switching signal. The resistance attenuation circuit 13 and the switching circuit 14 may be replaced with a variable attenuation circuit.

  In this embodiment, since the maximum amplitude value and the reference signal K having a constant value and the amplitude of the data signal D inserted between the reference signals K change due to fading or the like, every three data signals The reference signal K is inserted into the. Of course, the reference signal K may be inserted for each data signal, and conversely, four or more data signals D may be inserted between the reference signals K depending on the modulation frequency and fading conditions.

The output of the switching circuit 14 is 1 / f ₁ (in this embodiment, as shown in FIG. 2A) via a low-pass filtering circuit 16 for removing noise and high-frequency components generated at the time of switching. 4.8 kHz) A modulation signal whose amplitude value fluctuates every second is applied to the modulation circuit 17. The modulation frequency is 19.2 kHz. Since this modulated signal (a) includes a reference signal K having a constant amplitude every third period, there is a frequency component of 4.8 kHz / 4 = 1.2 kHz. Since it changes every cycle of 8 kHz, it is necessary to include at least a frequency component of 2.4 kHz that makes this a half cycle.

The modulation circuit 17 modulates the local carrier wave f ₂ (476.2 kHz in this embodiment) with the modulation signal [FIG. 2 (a)], and converts the modulated wave amplitude-modulated as shown in FIG. 2 (b). appear. Since this modulated wave (b) is a normal amplitude-modulated wave, it includes a local carrier wave, a lower side band wave, and an upper side band wave. FIG. 2C shows only the upper sideband. A waveform indicated by a dotted line in FIG. 2C is a waveform before band limitation.

This modulated wave (b) is filtered by the band-pass filtering circuit 18 having a center frequency f ₂ + nf ₁ (495.6 kHz in the case of n = 4 in this embodiment) and a bandwidth of 4.8 kHz. Only the wave passes and is output as a single sideband signal as shown in FIG.
The band-pass filtering circuit 18 in the conventional method is a large crystal filter having a very steep filter characteristic. In the case of this method, the frequency of the local carrier wave and the sideband wave can be greatly separated. It is not necessary to be steep and it is considered possible to make it an IC.

  Here, the pass band of the band-pass filtering circuit 18 is set to a minimum of 2.4 k × 2 = 4.8 kHz as a signal change width, but the band-pass filtering circuit 18 passes even if the filtering circuit 18 becomes large. In the case where priority is given to narrowing the bandwidth, it may be set to 2.4 kHz which is a half of that.

This single sideband signal (d) is mixed with the second local oscillation frequency f ₃ by the transmission mixing circuit 19, shifted up, amplified by the high frequency amplifier circuit 20, and filtered by the band pass filter circuit 21. Further, it is mixed with the first local oscillation frequency f ₄ by the transmission mixing circuit 22, amplified by the high frequency amplification circuit 23, filtered by the band pass filtering circuit 24, amplified by the transmission power amplification circuit 25, and the air battle tuning circuit 26 Then, it is transmitted from the antenna 27 at a frequency of f ₄ + f ₃ + F ₂ + nf ₁ .

When the local carrier wave is V ₀ cos ω _c t and the modulated wave is V _M costt, the amplitude modulated wave V (t) is expressed by the following equation.
V (t) = V ₀ cos ω _c t + 1/2 · kV _M / V ₀ · cos (ω _c + p) t + 1/2 · kV _M / V ₀ · cos (ω _c −p) t
Where k is a proportional multiplier

Here, when the upper side band V _U (t) is extracted by the filter, V _U (t) = ½ · kV _M / V ₀ · cos (ω _c + p) t. Thus, the upper side band V _U (t) has a single frequency, and its amplitude is proportional to the amplitude V _M of the modulated wave (V _M cost).

In the present invention, since the frequency of the modulated wave is constant, the band used by the sideband is a band necessary for placing the data signal on both sides or one side of the sideband (in this embodiment, 4.8 kHz or 2. 4 kHz) is sufficient. Accordingly, there is no restriction on the interval between the local carrier and the sideband, and it is desirable that the interval between the local carrier and the upper sideband be greatly separated in order to delete the local carrier.

  With this setting, the power of unnecessary emission such as local carrier waves and lower sidebands can be greatly reduced as compared with the conventional SSB system. Further, since the bandwidth to be used can be minimized, it is considered that the frequency utilization efficiency can be maximized.

  FIG. 3 is a diagram showing an overall configuration on the receiving side of the first SSB wireless communication system according to the embodiment of the present invention, and FIG. 4 is a diagram showing the overall configuration of the receiver side of the second SSB wireless communication system.

  The receiving-side radio receives the transmission wave described in FIG. 1 and the like, converts it to an intermediate frequency, performs automatic gain control and synchronous detection, and decrypts the data signal while guaranteeing the amplitude value. At the same time, the local oscillation frequency and the local carrier frequency, which are indispensable for the SSB system, are reproduced.

  First, in the SSB system, it is necessary to regenerate the local oscillation frequency and the local carrier frequency whose frequency and phase almost coincide with the carrier wave not included in the transmission wave on the receiving side. Conventionally, this reproduction may be difficult because the SSB method is not used in the VHF band or the UHF band. In the present invention, the following measures are adopted as countermeasures.

1. In the SSB system, the amplitude value of the sideband wave is proportional to the amplitude value of the modulated wave. In the present invention, the amplitude of the signal is switched every 1 / f ₁ second. In order to transmit this change accurately, a wide bandwidth is required, but in this proposal, only the fundamental wave component is transmitted. However, as shown in FIG. 2C, immediately before the signal is switched (point ↑), the amplitude value is almost the same as that before the frequency bandwidth is limited. Therefore, by measuring the amplitude of the sideband immediately before signal switching as in claim 1, digital data can be decoded without requiring synchronous detection. This eliminates the need for a local oscillation frequency and a local carrier frequency, which are necessary for synchronous detection, and whose frequency and phase are almost the same as those of the transmission-side carrier.

2. As in claim 2, on the transmission side, the frequency of the cycle of the reference signal K (in this embodiment, f ₁ /4=1.2 kHz), the local carrier frequency f ₂ and the local oscillation frequency (f ₃ , f ₄ ), The period does not change even if the frequency is converted on the receiving side. Therefore, the period frequency of the peak (reference signal K) of the received wave (specifically, the intermediate frequency signal) is detected and this is detected. If the local oscillation frequency for reception and the local carrier frequency are synchronized with each other, it is possible to always synchronize even if the transmitted frequency fluctuates.

  Next, the amplitude value of the received SSB wave decreases or fluctuates due to fading of the transmission path. The detection and compensation of the amplitude value is performed as follows.

Since the reference signal K having the maximum amplitude is inserted at regular intervals with the data signal carrying the amplitude value, first, the peak of the amplitude (the amplitude immediately before the reference signal K is switched) in the intermediate frequency signal. Is controlled so that the demodulation output (reference signal K) of the synchronous detection means is peak-detected and the amplitude of the reference signal K is controlled to be constant. Further, since the interval (k / f ₁ ) of the reference signal K can be made sufficiently smaller than the normally assumed minimum time constant (about 10 ms) of fading, it is easy to control the reference signal K to be constant. Further, the lowest frequency contained in the signal, because the frequency (f 1 _{/ k)} for the spacing of the reference signal and one cycle, the band-pass filter circuit 52, the frequency (f 1 _{/ k)} from the lower frequency And frequencies higher than the modulation frequency (nf ₁ ) can be removed. As a result, the influence of fading, noise, and the like can be made extremely small, so that the amplitude of the reference signal K can be made almost completely constant, and the data signal D can be accurately decoded based on this constant controlled reference signal K.

  Now, the reception operation of the SSB modulated wave (upper band frequency f4 + f3 + f2 + nf1) transmitted from the transmitting-side radio device by the antenna 31 will be described with reference to FIGS.

This received signal is input to the mixing circuit 35 via the band-pass filtering circuit 32, the high-frequency amplifier circuit 33, and the band-pass filtering circuit 34. In the mixing circuit 35, the input signal and the first local oscillation frequency f ₄ from the synthesizer circuit 39 are mixed, and the first intermediate frequency signal (frequency = f 3 + f 2 + nf ₁ ) is passed through the band-pass filtering circuit 36. Get.

The first intermediate frequency signal (frequency = f ₃ + f ₂ + nf ₁ ) is amplified by the intermediate frequency amplifier circuit 37. Further, the signal is mixed with the second local oscillation frequency f3 from the synthesizer circuit 39 by the mixing circuit 38, and is filtered by the band-pass filtering circuit 41 to become a second intermediate frequency signal (frequency = f ₂ + nf ₁ ).

  The output of the band pass filter circuit 41 is input to the intermediate frequency amplifier circuit 42. The output is input to the peak detection circuit 43, the peak is detected, and the output is input to the gain control circuit 44. With this input, the gain control circuit 44 controls the output of the intermediate frequency amplifier circuit 42 to be a constant value.

In FIG. 3, the amplitude measurement circuit 46 measures the amplitude value of the reference signal K of the output (c in FIG. 2) of the intermediate frequency amplification circuit 42 based on the signal from the peak detection circuit 45, and then 1 / f ₁ second. The data signal D is measured later (point ↑ in FIG. 2c). Then, k−1 data signals D are measured every 1 / f after ₁ second.

  In response to an input from the amplitude measurement circuit 45, the decoding circuit 46 outputs digital data from the measured value. In some cases, the measured values of all the data signals between the reference signals K (three in this embodiment) may be converted into digital data as one group.

  In FIG. 4, the output of the intermediate frequency amplification circuit 42 is input to the synchronous detection circuit 51, the peak detection circuit 43, and the peak detection circuit 58.

The peak detection circuit 58 detects the peak of the output (c in FIG. 2) of the intermediate frequency amplification circuit 42. Since this peak occurs immediately before the switching of the reference signal K, it is supplied to the synthesizer circuit 40 as a synchronization signal. The synthesizer circuit 40 generates a first local oscillation frequency f ₄ , a second local oscillation frequency f _3, and a local carrier frequency f ₂ based on the signal of the inputted synchronization signal (k / f inputted every ₁ second). To do. Since the frequency f ₁ is formed in synchronization with the first local oscillation frequency f ₄ on the transmission side, the first local oscillation frequency formed on the reception side based on the frequency f ₁ is the same as that on the transmission side. Basically match. Therefore, frequency conversion is performed in the same way on both the transmission side and the reception side.

The synthesizer circuit 40, since the local carrier frequency based on the input frequency f ₁ of the signal are formed, the local carrier frequency is synchronized with the sideband frequency components upon reception. Therefore, even if there is a slight frequency change in the received upper sideband frequency component, the local carrier frequency changes in response to the frequency change. (F ₂ ) and the receiving side local carrier frequency are the same.

  The output of the intermediate frequency amplifier circuit 42 and the output of the synthesizer circuit 40 (reception side local carrier wave) are input to the synchronous detection circuit 51, and the demodulated output [(d) of FIG. 2] is output from the synchronous detection circuit 51. In the demodulated output, the amplitude value immediately before the switching of the signal in each cycle (the point indicated by ↓) is substantially equal to the corresponding amplitude value on the transmission side.

  The output (demodulation output) of the synchronous detection circuit 51 is input to the low frequency amplification circuit 53 through the band filtering circuit 52. The output of the low frequency amplifier circuit 53 is input to the peak detection circuit 54. The peak detection circuit 54 detects the peak value of the reference signal K. The output of the peak detection circuit 54 is input to the gain control circuit 55, compared with the target reference value, and the low frequency amplification circuit 53 is automatically gain controlled based on the difference. As a result, the reference signal K output from the low frequency amplifier circuit 53 is controlled to a substantially constant value.

  The output of the low frequency amplifier circuit 53 is also input to the decoding circuit 56. In the decoding circuit 56, the amplitude value of the cycle immediately before the switching of the data signal D (point of ↓ in FIG. 2) and the amplitude value of the cycle immediately before the switching of the reference signal K (point of ↓ of FIG. 2) are made. The difference is measured and the digital data of the data signal D is output.

  Since the amplitude value slightly changes depending on the amplitude value of the previous signal, there is a margin for the error, or all the data signals D between the reference signal K and the next reference signal D are stored as one. By patterning as a set and measuring the amplitude value of each data signal D, it is possible to determine which pattern it is and convert the pattern into digital data.

  The communication system of the present invention can be used for the spread spectrum communication system (DS system). In this case, the present system has very high frequency utilization efficiency and can reduce the transmission power, so that the restriction on the number of channels in the DS system can be reduced.

The invention's effect

  In the present invention, the advantages of high power efficiency and narrow frequency band transmission in the SSB wireless communication system can be further expanded, and the frequency utilization efficiency can be greatly improved.

  In addition, the influence of fading can be reduced by the control and the demodulated band-pass filter circuit 52 for making the reference signal constant in the intermediate frequency amplifier circuit 40 and the low frequency amplifier circuit 53.

  In addition, since the local oscillation frequency and the local carrier frequency are adjusted in synchronization with the interval of the received reference signal, the synchronous detection circuit can synchronize the reception input with the local carrier frequency even if the oscillation circuit is not extremely high in stability. Is almost completely removed. Therefore, the demodulation efficiency is improved and the influence of noise and the like is reduced.

  From the above, it is possible to apply the SSB radio of the present invention to all frequency bands above the medium wave band, and the frequency utilization efficiency can be greatly improved in all frequency bands above the medium wave band. In the short wave band, not only can high-speed data be transmitted in a narrow band, but also the effect of fading can be reduced, so that the effect is particularly great.

  The figure which shows the whole structure of the radio | wireless machine of the transmission side of the SSB radio | wireless communication system which concerns on embodiment of this invention.   The figure which shows the waveform of each part of a radio | wireless machine.   The figure which shows the whole structure of the radio | wireless machine of the receiving side of the 1st SSB radio | wireless communication system based on embodiment of this invention.   The figure which shows the whole structure of the radio | wireless machine of the receiving side of the 2nd SSB radio | wireless communication system based on embodiment of this invention.   The figure which shows the block configuration of the receiving circuit of the radio | wireless machine using the conventional SSB radio | wireless communication system.

Explanation of symbols

11 Synthesizer circuits 12, 18, 20, 24 Band-pass filter circuit 13 Resistance attenuator 14 Switching circuit 15 Control circuit 16 Low-pass filter circuit 17 Amplitude modulation circuits 19, 22 Transmission mixing circuits 21, 23 High-frequency amplifier circuit 25 Transmission Power amplifier circuit 26 Antenna tuning circuit 27 Antenna 31 Antennas 32, 34, 36, 41, 52 Band-pass filtering circuit 33 High frequency amplifier circuits 35, 38 Mixing circuits 37, 42 Intermediate frequency amplifier circuits 39, 40 Synthesizer circuit 43 Peak detection circuit 44, 55 Gain control circuit 45 Amplitude measurement circuit 46, 57 Decoding circuit 51 Synchronous detection circuit 53 Low frequency amplifier circuit 56 Amplitude measurement circuit 58 Peak detection circuit 59 Synchronization signal generation circuit

Claims (2)

On the transmitting side, a sine wave-shaped reference signal having a constant amplitude and a predetermined width and a predetermined period, and a binary or multi-value having the same width as the reference signal and the amplitude of the reference signal as a reference A sine wave data signal with an amplitude representing the digital value of the signal as a modulation input, the carrier wave is amplitude-modulated and transmitted in a single sideband,
On the receiving side, the reception gain is automatically adjusted based on the reference signal, and the amplitude value of the carrier wave of the reception signal is set immediately before or after the switching of each signal with the amplitude value of the reference signal being a peak value as a reference. High-efficiency digital SSB radio characterized by measuring the amplitude value at an appropriate location and detecting the digital value A frequency generation means for generating a local carrier wave and a local oscillation wave from a common oscillation source, and a reference signal composed of a plurality of sine waves having a predetermined width, a predetermined period, and a constant amplitude based on the generated frequency of the frequency generation means And a modulation wave generation for generating a modulation wave composed of a sine wave data signal having the same width and the same number of sine waves as the reference signal and expressing a binary or multivalued digital value based on the amplitude of the reference signal. Means,
Modulation means for amplitude-modulating the local carrier wave with the modulated wave;
Bandpass filter means for passing only the upper or lower single sideband of the modulation output of this modulation means;
A frequency conversion means for shifting the output of the band pass filter means by the local oscillation wave to be a transmission carrier signal;
On the receiving side, the single sideband communication signal is shifted by a local oscillation frequency signal and converted to an intermediate frequency signal, an intermediate frequency amplification means for amplifying the intermediate frequency signal from the frequency conversion means, and A frequency detecting means for outputting a frequency component of the period of the reference signal from the output of the intermediate frequency amplifying means;
Based on the frequency generating means for generating the local oscillation frequency signal based on the frequency component of the period of the reference signal from the frequency detection means, the local carrier oscillation circuit synchronized with the local oscillation frequency, and the output thereof A high-efficiency digital SSB radio comprising a synchronous detection circuit for demodulating the received signal, and detecting the digital value of the signal from the amplitude value immediately before the signal is switched in the demodulated output of each signal

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