JPH1131988A - Receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To receive a superimposed transmission signal and to prevent the omission of information or the interrupt of communication by detecting the presence or absence of a large power signal contained in the received signals and setting the phase of a small power signal at a constant level by compensating the phase difference. SOLUTION: A receiving device 8 inputs the signals received via a nonlinear transmission line 3 to a large power signal extractor 7, a large power signal detector 4 and a small power signal extractor 5. The detector 4 detects the presence or absence of a large power signal contained in the received signals and outputs the detection information. Then a phase controller 6 reversely turns the phase of the output signal of the extractor 5 by a degree equivalent to a prescribed angle based on the detection information outputted from the gate signal generator of the detector 4 only when the large power signal exists. Thus, the controller 6 instantaneously sets the phase of a small power signal at a desired signal point. As a result, a constant phase is secured for the small power signal existing in a section including a large power signal and also for the small power signal existing in a section including no large power signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for communication in which a large power signal and a small power signal are superimposed and transmitted. INDUSTRIAL APPLICABILITY The present invention is suitable for use in satellite digital video communication using a superimposed transmission method in which a high power video signal and a low power audio signal are transmitted via the same satellite transponder. INDUSTRIAL APPLICABILITY The present invention is suitable for use in satellite interactive communication based on a superimposed transmission method in which a high power data signal and a low power request signal are transmitted via the same satellite transponder. The present invention converts a video signal to TDMA (Time Division Multiple Acces).
s) It is suitable for use in operating the transponder in a non-linear region when communicating in a burst mode such as the scheme.

[0002]

2. Description of the Related Art There is known a communication system in which a large power signal and a small power signal are transmitted in a superimposed manner. For example, in satellite communication, when a large power signal and a small power signal are transmitted through the same transponder, if the transponder is operated in the nonlinear region of the maximum output in order to make effective use of power, the transponder operates more efficiently than the linear region. AM (Amplitude Modulat
The phase of the small power signal rotates due to the ion) -PM (Phase Modulation) conversion characteristic.

Accordingly, when the high power signal is a burst signal such as a TDMA signal, the operation is performed in a non-linear region when a high power signal is present, and in a linear region when no high power signal is present. As a result, the phase of the small power signal instantaneously rotates greatly. Therefore, in order to control the rotation of the phase of the small power signal so as to keep the phase constant, an automatic phase control circuit that controls the phase of the small power signal from the phase information of the small power signal is applied.

[0004]

However, if an automatic phase control circuit that controls the phase of a small power signal based on the phase information of the small power signal is applied, first, the phase of the small power signal is observed, and the observation is performed. If the result is the rotation angle to be corrected, the operation is performed to correct and reverse the phase to the predetermined phase. Therefore, since there is a pull-in process of observation → reverse rotation angle determination → correction, it is difficult to always maintain a constant phase.

[0005] At this time, if the time constant of the automatic phase control circuit is longer than the ON / OFF cycle of the high power signal, the automatic phase control circuit cannot follow the signal and cannot demodulate, resulting in loss of information or interruption of communication.

The present invention has been made in such a background, and the phase of a small power signal in a section containing a large power signal and the phase of a small power signal in a section not containing a large power signal are made constant. It is an object of the present invention to provide a receiving device capable of performing the above. SUMMARY OF THE INVENTION It is an object of the present invention to provide a receiving apparatus that receives a superimposed transmission signal and does not cause loss of information or interruption of communication.

[0007]

SUMMARY OF THE INVENTION A receiving apparatus according to the present invention receives a superimposed transmission signal in which a large power signal and a small power signal are transmitted through the same nonlinear transmission path, and outputs a large power signal from the received signal. The presence or absence of a large power signal is detected, and when a large power signal is present, the phase of the small power signal is superimposed on the large power signal and reversely rotated by an amount equivalent to the rotation of the small power signal. The most important feature is that the phase is corrected and the phase is fixed instantaneously.

That is, according to the present invention, a large power signal and a small power signal are superimposed and transmitted via a non-linear transmission path, and a large power signal is included and a large power signal is not included. A receiving apparatus includes means for receiving a superimposed transmission signal having a phase difference and extracting a large power signal and a small power signal from the received signal. According to a feature of the present invention, the extracting means includes means for detecting whether or not a received signal includes a large power signal, and compensating the phase of the small power signal in accordance with the detection result. And means for making the phase constant. The phase difference is constant for each transmission path, and the means for setting the constant phase preferably includes means for rotating the phase angle in a direction to compensate for the phase difference.

Therefore, as soon as the detection result of the detecting means is obtained, the phase can be instantaneously compensated by rotating the phase at a constant angle in the direction for compensating the phase difference. In a conventional automatic phase control circuit,
The phase rotation direction of the input signal is observed, and the rotation direction for compensation is determined according to the observation result.Compensation is performed. Become. According to the present invention, since it is not necessary to perform such observation, the phase difference can be compensated without creating a state in which the phase of the input signal remains rotated.

[0010]

Embodiments of the present invention will be described with reference to FIG. FIG. 1 is an overall configuration diagram of the first embodiment of the present invention.

According to the present invention, the high power signal and the low power signal are superimposed and transmitted via the non-linear transmission line 3 and the phase difference between the low power signal and the high power signal is not different between when the high power signal is included and when the high power signal is not included. Is a receiving device 8 provided with a large power signal extractor 7 and a small power signal extractor 5 as means for receiving a superimposed transmission signal in which a signal occurs and extracting a large power signal and a small power signal from the received signal.

Here, a feature of the present invention is that the small power signal extractor 5 includes a large power signal detector 4 as means for detecting whether a received signal contains a large power signal.
And a phase adjuster 6 as a means for compensating the phase difference of the small power signal to a constant phase according to the detection result.

[0013]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is as described above. FIGS. 2 to 4 are views showing the status of each part of the first embodiment of the present invention. FIG. 5 is a block diagram of the high power signal detector 4. FIG. 6 is a block diagram of the small power signal extractor 5. FIG. 7 is a diagram for explaining the operation of the level adjuster 6.

In FIG. 1, on the transmitting side, a burst mode high power signal having a carrier frequency f1 as shown in FIG. Also, as shown in FIG. 2B, the small power signal transmitting device 2 outputs a small power signal of the carrier frequency f2. The outputs of the burst mode high power signal transmission device 1 and low power signal transmission device 2 are transmitted to the same non-linear transmission path 3 as shown in FIG.

The receiving device 8 converts the signal received from the nonlinear transmission path 3 into a high power signal extractor 7 and a high power signal detector 4
And the small power signal extractor 5. The description of the high power signal extractor 7 is omitted because it is not directly related to the present invention. The high power signal detector 4 detects the presence or absence of a high power signal from the received signal and outputs detection information.

As shown in FIG. 5, in the high power signal detector 4, the received signal power is measured by the envelope detector 20, and if the power exceeds a predetermined threshold value, it is assumed that the high power signal exists. The gate signal generator 21 outputs detection information.

The low power signal extractor 5 extracts only a low power signal from the received signal. As shown in FIG. 6, the small power signal extractor 5 extracts and outputs the small power signal by the bandpass filter 30 that passes only the band f2 in which the small power signal is transmitted.

FIG. 4A shows the phase of the signal point arrangement of the small power signal when there is no large power signal.
As shown in (1), when a large power signal is present, the phase of the signal point arrangement of the small power signal is rotated by an angle θ. Is different for each transmission path, but is constant for each transmission path. Thereby, the angle −θ for compensating for this angle θ is obtained.
Can also be fixed beforehand for each transmission path.

As shown in FIG. 7, the phase adjuster 6 adjusts the phase of the output signal of the small power signal extractor 5 according to the detection information output from the gate signal generator 21 of the large power signal detector 4. Only when a signal is present, the angle θ is reversely rotated by the phase shifter 22, and even when a large power signal is present, the phase of the small power signal is instantaneously changed to the desired signal point as shown in FIG. Arrangement.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is an overall configuration diagram of the second embodiment of the present invention. 9, 10, 14 to 16
FIG. 8 is a view showing the status of each part of the second embodiment of the present invention. FIG.
1 is low power SSMA (Spread Spectrum Multiple Acces)
s) is a block diagram of the signal transmission device 9. FIG. FIG. 12 and FIG. 13 are block diagrams of the low power SSMA signal extractor 10. 8, on the transmitting side, the burst mode high power signal of the carrier frequency f1 is output from the burst mode high power signal transmitting apparatus 1 as shown in FIG. 9A. Further, as shown in FIG. 9B, the low power SSMA signal transmitting device 9 outputs a low power SSMA signal having the carrier frequency f1. When a low power signal as shown in FIG. 14 (a) is input to the low power SSMA signal transmitting device 9, the spectrum is spread by a spread spectrum code as shown in FIG. 11 and is shown in FIG. 14 (b). A small power signal having such a spread spectrum is obtained.

The outputs of the burst mode high power signal transmitting device 1 and low power SSMA signal transmitting device 9 are transmitted to the same nonlinear transmission path 3 and superimposed as shown in FIGS. 10 (a) and 10 (b). Transmitted.

On the receiving side, the signal received from the nonlinear transmission path 3 is input to the high power signal extractor 7, the high power signal detector 4, and the low power SSMA signal extractor 10. The high power signal detector 4 detects the presence or absence of a high power signal from the received signal and outputs detection information. This detection procedure is as described with reference to FIG.

The low power SSMA signal extractor 10 extracts a low power SSMA signal from the received signal. The received signal is shown in FIG.
This is as shown in (a), and the received signal is despread by a spread spectrum signal corresponding to that used in the low power SSMA signal transmitter 9 as shown in FIG. The despread received signal is as shown in FIG.
The despread reception signal is further passed through only the original signal band of the low power SSMA signal by the band pass filter 30 shown in FIG. 12 to obtain a signal as shown in FIG.

Alternatively, as shown in FIG.
A high power signal demodulator 31 and a high power signal re-modulator 32 are provided in the SMA signal extractor 10, and a received signal as shown in FIG. 16A is demodulated once as shown in FIG. 16B. The high-power signal is re-modulated, a replica of the high-power signal is generated, and the generated high-power signal replica is reverse-phase-combined with the received signal to cancel the high-power signal.
A small power signal as shown in FIG. 6 (c) is obtained. This small power S
By multiplying the SMA signal by the spread spectrum code corresponding to the spread spectrum code used on the transmission side,
After the spectrum is despread to the original signal band of the low power SSMA signal as shown in (d), as shown in FIG. 16 (e), the bandpass filter 30 passes only the original signal band of the small power signal. It extracts and outputs only low power signals.

In the second embodiment of the present invention, similarly to the first embodiment of the present invention, the phase adjuster 6 is provided with a low power SSMA signal extractor 10.
The phase of the output signal is reversely rotated only when there is a large power signal based on the detection information of the large power signal detector 4, and the phase difference of the small power signal can be instantaneously compensated.

As described above, when a burst mode high power signal and a low power signal are transmitted simultaneously via a non-linear transmission line, the phase fluctuation of the low power signal due to the rotation of the phase caused by the presence or absence of the high power signal is corrected. , A constant phase can be realized instantaneously. The present invention is applied to a communication system using a non-linear transmission line, and its effect is great.

[0027]

As described above, according to the present invention,
The phase of the small power signal in the section containing the large power signal and the phase of the small power signal in the section not containing the large power signal can be made constant. Thus, it is possible to realize a receiving apparatus that does not lose information or interrupt communication when receiving and demodulating a superimposed transmission signal.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram showing the status of each part of the first embodiment of the present invention.

FIG. 3 is a diagram showing the status of each unit according to the first embodiment of the present invention.

FIG. 4 is a diagram showing the status of each part of the first embodiment of the present invention.

FIG. 5 is a block diagram of a high power signal detector.

FIG. 6 is a block diagram of a small power signal extractor.

FIG. 7 is a diagram for explaining the operation of the level adjuster.

FIG. 8 is an overall configuration diagram of a second embodiment of the present invention.

FIG. 9 is a diagram showing the status of each part of the second embodiment of the present invention.

FIG. 10 is a diagram showing the status of each part of the second embodiment of the present invention.

FIG. 11 is a block diagram of a low power SSMA signal transmitting apparatus.

FIG. 12 is a block diagram of a small power SSMA signal extractor.

FIG. 13 is a block diagram of a low power SSMA signal extractor.

FIG. 14 is a diagram showing the status of each part of the second embodiment of the present invention.

FIG. 15 is a diagram showing the status of each part of the second embodiment of the present invention.

FIG. 16 is a diagram showing the status of each part of the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Burst mode high power signal transmitter 2 Low power signal transmitter 3 Non-linear transmission line 4 High power signal detector 5 Low power signal extractor 6 Phase adjuster 7 High power signal extractor 8 Receiver 9 Low power SSMA signal transmitter DESCRIPTION OF SYMBOLS 10 Low power SSMA signal extractor 20 Envelope detector 21 Gate signal generator 22 Phase shifter 30 Bandpass filter 31 High power signal demodulator 32 High power signal remodulator

Claims (2)

[Claims] 1. A superposition in which a large power signal and a small power signal are superimposed and transmitted via a non-linear transmission path, and a phase difference occurs in the small power signal when the large power signal is included and when the large power signal is not included. A receiving device comprising means for receiving a transmission signal and extracting a large power signal and a small power signal from the received signal, wherein the extracting means determines whether the received signal contains a large power signal. And a means for compensating the phase difference and setting the phase of the small power signal to a constant phase according to the detection result. 2. The receiving apparatus according to claim 1, wherein the phase difference is constant for each transmission path, and the means for setting the constant phase includes a means for rotating a phase angle in a direction for compensating the phase difference.