JPH11145886A - Reproducing/repeating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reproducing/repeating device, which enables normal demodulation and can perform normal and stable reproducing/repeating. SOLUTION: In a reproducing/repeating device 1A which is provided with a transmission antenna 11 and a reception antenna 17, this device is provided with a cancellation signal control circuit 18 for cancelling a creeping signal to turn into the reception antenna 17 after transmission from the transmission antenna 11 and with a delay circuit 20A. In the above configuration, a part for generating an error component and a part with unstabilized symbol of the desired signal are overlapped so as not to allow the part to generate the error component, after cancel lation and a part with stabilized symbol of the desired signal to be overlapped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative repeater for regeneratively relaying a radio signal, and more particularly, to an improvement of a regenerative repeater employing a self-loop interference canceling system.

[0002]

2. Description of the Related Art When a regenerative repeater for generating and transmitting a radio reproduction signal having the same frequency as a radio reception signal is used in an open space, it is necessary to sufficiently consider the physical arrangement of a transmission antenna and a reception antenna. In particular, when the distance between the antennas is short, if the coupling between the two antennas is large, a failure such as oscillation may occur, and normal relay service may not be possible. This is because the ratio between the level at which the output of the regenerative repeater goes around and enters the receiving antenna and the level of the radio signal from the base station, which is originally intended for relaying, is determined by the D at which the demodulator of the present repeater can operate normally. Occurs when the ratio falls below the / U ratio.

[0003] In order to solve this problem, a technique for reducing the coupling between the antennas by devising the directivity of the transmitting antenna and the receiving antenna, and a method of removing interference from the local station have been known.

[0004] A regenerative repeater employing a self-station wraparound interference elimination system will be described below. FIG. 6 is a block diagram showing a regenerative repeater adopting the self-station wraparound interference elimination method. In the regenerative repeater 1 shown in FIG.
0 indicates a regeneration relay circuit. Reference numeral 11 denotes a receiving antenna. The receiving antenna 11 is an antenna for the regenerative repeater 1 to receive a radio wave (desired signal) intended for relay. Reference numeral 12 denotes a receiving circuit whose input side is connected to the receiving antenna 11 and which receives the output of the receiving antenna 11 as an input and outputs a received signal.

In the regenerative repeater 1, reference numeral 13 is connected to the output side of the receiving circuit 12 and to the output side of a cancel signal adjusting circuit to be described later.
This is an addition circuit that adds the reception signal from the second signal and the cancellation signal from the cancellation signal adjustment circuit and outputs the result. 1
A demodulation circuit 4 is connected to the output side of the addition circuit 13 and performs demodulation by using an output of the addition circuit 13 as an input. A demodulation circuit 15 is connected to an output side of the demodulation circuit 14 and remodulates a demodulated signal of the demodulation circuit 14. This is the modulation circuit to be used.

Further, in the regenerative repeater 1, reference numeral 16 denotes a transmission circuit connected to the output side of the modulation circuit 15 for generating and outputting a radio output signal from the modulation signal output from the modulation circuit 15; A transmitting antenna connected to the output side of the antenna and emitting radio waves as a relay output; and 1
Numeral 8 is connected to the output side of the modulation circuit 15 and adjusts the phase, amplitude and delay of the output of the modulation circuit 15 so that the same amplitude and delay time as the wraparound signal component included in the output signal of the reception circuit 12 are obtained. A cancel signal adjusting circuit that generates a signal having the opposite phase and outputs the generated signal as a wraparound signal cancellation signal for canceling the wraparound signal.

As shown by such a configuration, in the conventional regenerative repeater 1, the replica of the wraparound component is subtracted from the received signal which is a composite signal of the desired signal and the wraparound signal component from the transmitting antenna. Then, a desired signal is extracted by removing the wraparound component. Then, by passing this desired signal to the demodulation circuit 14 at the subsequent stage, normal demodulation and re-modulation are performed.

[0008]

However, in the prior art, the technique of reducing the coupling between the antennas by devising the directivity of the transmitting antenna and the receiving antenna cannot match the directivity corresponding to the area where the relay service is desired. There is a problem that a case may occur. In addition, there is a limit to the amount of coupling reduction between the transmitting and receiving antennas, and furthermore, there is a problem that the cost of the antenna is greatly increased.

On the other hand, the technique using the self-station sneak interference canceling system shown in FIG. 6 is effective because the sneak signal component is positively canceled in the self-station, but is effective in outputting the actual subtraction result. The signal contains a slight error between the wraparound component and the wraparound cancel signal as a residual error. This residual error is caused by waveform distortion or delay error given by band limitation in a transmission line (particularly a channel filter). In the vicinity of a change point of a wraparound component and a modulation symbol of a wraparound cancellation signal synchronized with the wraparound component, this residual error is generated. The error amount becomes extremely large. This residual error may give a great obstacle to the demodulation operation in the regenerative repeater.

FIG. 7 is a time chart showing the timing of each signal of the conventional apparatus shown in FIG. 6 in order to show a case where the above-mentioned residual error gives a great obstacle to the demodulation operation in the regenerative repeater. In each of FIGS. 7A to 7E, the horizontal axis represents a common time axis. (A) of FIG.
And (B) respectively show the wraparound component of the received signal and the change timing (marked by X) of the modulation symbol in the cancel signal. The change timings of the modulation symbols in (A) and (B) are adjusted by the cancel signal adjustment circuit 18 so as to be substantially the same, and therefore are shown at substantially the same timing on the time axis.

(C) is a signal after cancellation, that is,
The output signal of the adder circuit 13 is shown. According to this,
This shows that the error (cancellation residual) component increases near the data change timing. This is due to the above-described waveform distortion and delay error.

(D) shows the timing of the change of the modulation symbol of the desired signal in the received signal. The relationship between the change timing of (A) (which is equal to the change timing of (B) and (C)) and the change timing of (D) are coincident because the delay time of each circuit element in the device is taken into account. Is not limited (usually does not match). FIG. 7 illustrates a case where there is a shift of a half time length of the symbol timing.

The signal input to the actual demodulation circuit is (C)
This is the sum of the signals shown in (D), and the timing of the change is shown in (E). (E) shows (C) and (D) in FIG.
(This is where the error of (C) is large) indicates that the symbol of the original desired signal (D) overlaps with a stable portion. Therefore, if the error component is large, there is a problem that the demodulation operation is not affected by the component and the desired signal cannot be demodulated normally.

The present invention has been made to solve such a problem, and a normal error is prevented by preventing a portion where an error component after cancellation is generated from overlapping with a portion where a symbol of a desired signal is stable. It is an object of the present invention to obtain a regenerative repeater capable of performing a proper demodulation and performing a normal and stable regenerative repeat.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a receiving antenna 11 for receiving a radio wave and a receiving antenna 11 as shown in FIGS. A receiving circuit 12 to which an output signal is input;
A demodulation circuit 14 for demodulating a desired reception signal output from the reception circuit 12, a modulation circuit 15 for modulating a demodulation signal output from the demodulation circuit 14, and a modulation signal output from the modulation circuit 15 Transmitting circuit 16 for transmitting
A transmission antenna 17 for transmitting an output signal of the transmission circuit 16 as a radio wave; and a wraparound cancellation for canceling a transmission signal from the transmission antenna 17 received by the reception antenna 11 based on the modulation signal. A cancel signal adjustment circuit 18 for outputting a signal; and a reception signal demodulated by the demodulation circuit 14 by adding the wraparound cancellation signal output by the cancellation signal adjustment circuit 18 to a reception signal output by the reception circuit 12. An adder circuit 13 for forming a desired signal; and a delay circuit 2 for delaying the timing of the desired reception signal or the modulation symbol such that the timing phase of the modulation symbol of the desired reception signal is the same as that of the modulation symbol of the loop cancel signal.
0A to 20D.

According to such a configuration, the timing of the desired reception signal or the modulation symbol can be delayed so that the timing phase of the modulation symbol of the desired reception signal is the same as that of the modulation symbol of the loop cancel signal. Therefore, it is possible to overlap the portion where the error component after the cancellation of the wraparound signal occurs and the portion where the symbol of the desired signal is not stable, that is, the portion where the error component after the cancellation of the wraparound signal occurs and the desired signal. Therefore, normal demodulation can be performed, and normal and stable regenerative relay can be performed.

In the present invention, the delay circuit includes a low-pass filter or a band-pass filter having a predetermined delay time.

Further, in the present invention, the delay circuit 20A is provided on the output side of the modulation circuit 15, as shown in FIG.

Further, according to the present invention, the modulation circuit 15 is constituted by a digital circuit, and the delay circuit 20A is constituted by a shift register for delaying a modulation signal represented by a digital value output from the modulation circuit. It is.

In the present invention, the delay circuit 2
As shown in FIG. 3, OB is a digital circuit provided on the output side of the demodulation circuit 14.

According to such a configuration, the signal form of the digital output of the demodulation circuit 14 can be delayed by the delay circuit 20B as it is, and the handling of the signal becomes easy.

In the present invention, the delay circuit 2
0C is provided on the input side of the demodulation circuit as shown in FIG.

Further, in the present invention, the delay circuit 20D is provided on a clock supply line which is an output line of a symbol timing generation circuit 19 for supplying a clock for generating a modulation signal to the modulation circuit 15,
By delaying the clock, the modulation signal is delayed.

According to such a configuration, the modulation symbol timing can be varied within one symbol, so that the delay control can be easily performed.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a diagram showing a reproduction relay device according to Embodiment 1. In the regenerative repeater 10A of the regenerative repeater 1A shown in FIG. 1, the same reference numerals as those in FIG. 6 denote the same or corresponding parts as those shown in FIG. 6, and a description thereof will be omitted. In the figure, reference numeral 20A denotes a delay circuit provided between the output side of the modulation circuit 15 and the input side of the transmission circuit 16, and the output side of the delay circuit 20A is connected to the input side of the cancel signal adjustment circuit 18.

The delay circuit 20A delays the change timing of the modulation symbol of the desired signal output from the modulation circuit 15 so that the change timing of the modulation symbol in the residual error is a portion where the symbol of the desired signal is stable. And do not overlap with, that is,
This delay circuit 20A causes the modulation symbol change timing in the residual error to be synchronized with the same timing as the portion where the symbol of the desired signal is not stable.

The operation of the first embodiment will be described below. FIG. 2 is a flowchart showing the timing of each unit of the regeneration relay circuit 1A shown in FIG. Each figure (a) in FIG.
In (f), the horizontal axis represents a common time axis.
FIGS. 2A and 2B show the wraparound component of the received signal and the change timing (marked by X) of the modulation symbol in the cancel signal, respectively. Since the change timings of the modulation symbols in (a) and (b) are adjusted to be substantially the same by the cancel signal adjustment circuit 18, they are illustrated at substantially the same timing on the time axis.

(C) is a signal after cancellation, that is,
The output signal of the adder circuit 13 is shown. According to this,
This shows that the error (cancellation residual) component increases near the data change timing. This is due to the above-described waveform distortion and delay error.

(D) shows the timing of changing the modulation symbol of the desired signal in the received signal. The relationship between the change timing of (a) (which is equal to the change timing of (b) and (c)) and the change timing of (d) is determined by the delay circuit 20
A is achieved by adjusting the delay time of A.

The signal input to the actual demodulation circuit is (c)
This is the sum of the signals shown in (d), and the timing of the change is shown in (e). (E) shows (c) and (d) of FIG.
(This is where the error of (c) is large) overlaps the original change timing of the desired signal (d) and deviates from the section where the modulation symbol of the desired signal is stable. Is shown.

Therefore, the demodulation operation is performed in this stable section, and the section where the error component near the change point of the modulation symbol of the desired signal is large is provided on the output side of the modulation circuit 15 so as not to be demodulated. By adjusting the delay time of the delay circuit 20A, it is possible to accurately demodulate the desired signal.

(F) shows a timing example of the integration discharge in demodulation. (F) shows an integral discharge operation of a binary modulation symbol as an example. As shown in the figure, the triangular integrated discharge pattern avoids a section in which the error component in the signal (e) before demodulation is large, and therefore has no effect on the demodulation result.

The delay circuit 20A can be constituted by, for example, a low-pass filter or a band-pass filter having a predetermined delay time. Further, when the modulation circuit 15 is constituted by a digital circuit, the modulation signal represented by a digital value output from the modulation circuit 15 can be delayed using a digital circuit such as a shift register or a latch.

The delay time is obtained by experimentally obtaining a time difference between a portion (timing) where an error component occurs after cancellation of the loop signal in the regenerative relay circuit and a timing at which the symbol of the desired signal changes. Alternatively, the time difference may be determined during the relay, and the delay time may be automatically adjusted according to the determined time difference. This is because, for example, two peaks appear at the timing of the D wave and the timing of the U wave by performing a correlation operation (complex correlation of I / Q) between the reception wave including the D wave and the U wave and the transmission wave. The delay time of the delay circuit can be set based on the difference between the peaks.

Embodiment 2 FIG. 3 is a diagram showing a regeneration relay device according to Embodiment 2. In the regenerative repeater circuit 10B of the regenerative repeater 1B shown in FIG. 3, the same reference numerals as those in FIG. 6 denote the same or equivalent objects as those shown in FIG.
The description here is omitted. The second embodiment is different from the first embodiment in that the delay circuit 20B is provided between the output side of the demodulation circuit 14 and the input side of the modulation circuit 15. In such a configuration, the same operation as in the first embodiment is performed, and it is apparent that the same operation and effect as in the first embodiment can be obtained. In this case, the delay circuit 2
0B is provided immediately after the demodulation circuit 14, the delay circuit 20B
B can be easily constituted by a digital circuit.

Embodiment 3 FIG. 4 is a diagram showing a reproduction relay apparatus according to Embodiment 3. In the regenerative repeater circuit 10C of the regenerative repeater 1C shown in FIG. 4, the same reference numerals as those in FIG. 6 denote the same or equivalent objects as those shown in FIG.
The description here is omitted. In the third embodiment, delay circuit 20C is provided between the output side of adder circuit 13 and the output side of demodulation circuit 14. Then, even in such a configuration, the same operation as that of the first embodiment is performed, and it is apparent that the same operation and effect as those of the first embodiment can be obtained.

Embodiment 4 FIG. FIG. 5 is a diagram showing a regenerative repeater according to the fourth embodiment. In the regenerative repeater circuit 10D of the regenerative repeater 1D shown in FIG. 5, the same reference numerals as those in FIG.
The description here is omitted. In the fourth embodiment, the delay circuit 20D is provided between the output side of the symbol timing generation circuit 19 and a clock input terminal for generating a modulation signal of the modulation circuit 15. The symbol timing generation circuit 19 is a circuit that supplies a clock (symbol timing) for generating a modulation signal to the modulation circuit 15.

According to such a configuration, the timing of the modulation symbol can be made variable within one symbol.
Delay control within one symbol can be easily realized. As is apparent from the time chart of FIG. 2, the delay control amount of the required timing is sufficient if it can be adjusted forward or backward by a maximum of 0.5 symbols (one symbol in total). The configuration of 4 is effective.

[0039]

As described in detail above, according to the present invention, in the regenerative repeater, by providing a delay circuit, a portion where an error component after cancellation is generated and a portion where a symbol of a desired signal is stable. Are not overlapped, so that even if a cancellation residual error occurs due to an error in the frequency characteristics or delay between the loop of the loop propagation path and the loop cancel signal, a correct demodulation of the desired signal can be performed. It is possible to provide an effective reproduction relay service. Since the present invention can be configured by simply providing a delay circuit in the conventional regenerative repeater, there is no problem in reducing the size and cost of the device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a regenerative repeater according to Embodiment 1 of the present invention.

FIG. 2 is a time chart showing the operation of the embodiment of the present invention.

FIG. 3 is a block diagram showing a regenerative repeater according to Embodiment 2 of the present invention.

FIG. 4 is a block diagram showing a regenerative repeater according to Embodiment 3 of the present invention.

FIG. 5 is a block diagram showing a regenerative repeater according to Embodiment 4 of the present invention.

FIG. 6 is a block diagram showing a conventional reproduction relay device.

FIG. 7 is a time chart showing the operation of a conventional reproduction relay device.

[Explanation of symbols]

 1A, 1B, 1C, 1D regeneration repeater 10A, 10B, 10C, 10D regeneration repeater circuit 11 transmission antenna 12 reception circuit 13 adder 14 demodulation circuit 15 modulation circuit 16 transmission circuit 17 transmission antenna 18 cancel signal adjustment circuit 20A, 20B, 20C, 20D delay circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Suzuki 1964, Makin, Miyamae-ku, Kawasaki-shi, Kanagawa

Claims (7)

[Claims] 1. A receiving antenna for receiving a radio wave, a receiving circuit to which an output signal of the receiving antenna is input, a demodulation circuit for demodulating a desired reception signal output from the receiving circuit, and an output from the demodulation circuit. A modulation circuit that modulates the demodulated signal to be transmitted, a transmission circuit that transmits a modulation signal output by the modulation circuit, a transmission antenna that transmits an output signal of the transmission circuit as radio waves, A cancel signal adjustment circuit that outputs a wraparound cancellation signal for canceling a transmission signal from the transmission antenna received by the reception antenna, and the wraparound cancellation signal output by the cancellation signal adjustment circuit is received by the reception circuit. And an addition circuit for adding a reception signal output by the above to form a desired reception signal demodulated by the demodulation circuit. When, as in the timing phase of the modulation symbols of the desired received signal and the cancellation signal sneak above the same, comprising a delay circuit for delaying the timing of the modulation symbol regeneration repeater. 2. The delay circuit according to claim 1, wherein said delay circuit comprises a low-pass filter or a band-pass filter having a predetermined delay time.
A regenerative repeater as described. 3. The regenerative repeater according to claim 1, wherein the delay circuit is provided on an output side of the modulation circuit. 4. The modulation circuit according to claim 1, wherein the modulation circuit comprises a digital circuit, and the delay circuit comprises a shift register for delaying a modulation signal represented by a digital value output from the modulation circuit. A regenerative repeater as described. 5. The regenerative repeater according to claim 1, wherein the delay circuit comprises a digital circuit and is provided on an output side of the demodulation circuit. 6. The regenerative repeater according to claim 1, wherein the delay circuit is provided on an input side of the demodulation circuit. 7. The delay circuit is provided on a clock supply line that supplies a clock for generating a modulation signal to the modulation circuit, and delays the clock by delaying the clock. Item 2. A regenerative repeater according to Item 1.