JPH07162386A - Method for reproducing multiplex modulated wave - Google Patents

Abstract

PURPOSE:To reproduce a received multiplex modulated wave without ghost by multiplexing the modulated wave of an in-phase carrier wave and that of a specified orthogonal carrier wave whose phase differs from that of the in-phase carrier. CONSTITUTION:The received multiplex modulated wave F is inputted to a video carrier wave reproduction part 1 to reproduce a video carrier wave A video modulated wave reproduction part 2 inputs the multiplex modulated wave F and the video carrier wave, equalizes the waveform of the demodulated video signal and reproduces a video modulated wave FV. The phase of the video carrier wave inputted to the video carrier wave phase shift part 31 of an audio, modulated wave reproduction part 3 is shifted by pi/2 to obtain the orthogonal carrier wave. It is synchronously demodulated and equalized in waveform together with the multiplex modulated wave F to obtain a sound signal A'. A video carrier phase shift part 32 adjusts the phase shift of the inputted video carrier wave and reproduces the orthogonal carrier wave whose phase difference is pi/2 with the video modulated wave. An orthogonal carrier wave modulation part 35 modulates it by the audio signal A'. A synthesis part 4 synthesizes the video modulated wave FV with the modulated wave FA and outputs the multiplex modulated wave F.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reproducing a multiple modulated wave used for separating and re-multiplexing a multiple modulated wave represented by, for example, an EDTV system.

[0002]

2. Description of the Related Art At present, it is difficult for a television retransmitting relay station and a television co-reception facility to obtain a good receiving location without ghost interference due to various reasons. Therefore, a so-called television relay technique is required which receives a television broadcast signal, removes a ghost signal from the received television broadcast signal, and then retransmits the ghost signal.

This television relay technology reproduces television broadcast waves so that the reception frequency of the broadcast waves matches the transmission frequency of the facility, or the input and output frequencies of the ghost elimination device match. Therefore, various developments are currently being made.

[0004]

By the way, the above-mentioned television relay technique is AM-modulated by a conventional television broadcast wave, that is, a video signal, is also FM-modulated by an audio signal, and is again AM-modulated and transmitted. It is a technology that corresponds to what we are doing. However, such a television relay technique modulates a television broadcast wave of the EDTV system that has recently appeared, that is, a video modulated wave obtained by modulating a video carrier and a carrier whose phase is π / 2 different from that of the video carrier. It is not a technique that corresponds to the multiplexed modulated wave obtained by multiplexing the obtained multiplexed signal modulated wave.

Therefore, in the conventional television relay technology, the video signal and the multiple signal are demodulated from the multiple modulated wave, and the multiple modulated wave is reproduced again after the equalization processing such as the ghost signal removal is performed. It cannot be retransmitted. Therefore, there is an urgent need to develop a reproducing technique for multiple modulated waves represented by the EDTV system.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, to receive a multiple modulated wave represented by the EDTV system to demodulate a video signal and a modulated signal, and to remove a ghost signal. It is an object of the present invention to provide a technique for reproducing a multiple modulated wave after equalization processing. The object of the present invention is to obtain a first modulated wave by modulating a in-phase carrier wave and a second modulated wave by modulating a quadrature carrier wave whose phase is π / 2 different from that of the in-phase carrier wave. The second step, the third step of multiplexing the first modulated wave obtained in the first step and the second modulated wave obtained in the second step, and the third multiplexing step And a fourth step of regenerating the obtained multiplex modulated wave.

Another object of the present invention is to modulate the in-phase carrier wave to obtain a first modulated wave, and to modulate the in-phase carrier wave and a quadrature carrier wave whose phase is different from that of the in-phase carrier wave by π / 2. A second step of obtaining a wave, and a third step of multiplexing the first modulated wave obtained in the first step and the second modulated wave obtained in the second step
And a fourth step of regenerating the multiplex modulated wave obtained in the third multiplexing step, wherein the fourth step comprises Reproducing the in-phase carrier and re-modulating this in-phase carrier to obtain the first modulated wave; and A, regenerating the quadrature carrier from the multiple modulated wave and re-modulating this quadrature carrier to obtain in step A above. A second modulated wave whose phase is π / 2 different from that of the first modulated wave B
And a step C of synthesizing the first modulated wave obtained in the step A and the second modulated wave obtained in the step B. Is also achieved.

The step A is a step of regenerating an in-phase carrier wave from the multiplex modulated wave, a demodulation step of demodulating the first modulated signal from the multiplex modulated wave using the in-phase carrier wave, and a demodulation step in this demodulating step. It is preferable to include a step of signal-processing the first modulated signal described above, and a step of remodulating the in-phase carrier with the signal-processed first modulated signal. Also, the above B
The step of reproducing the in-phase carrier wave from the multiplex modulated wave, obtaining the quadrature carrier wave by shifting the in-phase carrier wave by π / 2, and using the quadrature carrier wave to obtain the second modulated signal from the multiplex modulated wave. It is preferable to have a step of demodulating the signal, a step of processing the second modulated signal, and a step of remodulating the quadrature carrier with the signal-processed second modulated signal.

In the step B, the in-phase carrier is regenerated from the multiple modulation wave, the in-phase carrier is shifted by π / 2 to obtain the first quadrature carrier, and the first quadrature carrier is used. To demodulate a second modulated signal from the multiplex modulated wave, to process the second modulated signal, and to reproduce the first modulated wave and the reproduced second modulated wave. To obtain a second quadrature carrier by phase-shifting the in-phase carrier so that the phase difference becomes π / 2, and remodulating the second quadrature carrier with the signal-processed second modulated signal. It is preferable to have and.

Further, the modulated signal is preferably a video signal or an audio signal. Also, the modulated signal is preferably a digital signal or an analog signal.
Further, it is preferable that waveform equalization is performed in the step of performing signal processing on the modulated signal.

[0011]

The operation of the present invention will now be described. As shown in FIG. 1, an in-phase carrier wave is regenerated from the received multiplex modulated wave, and the first modulated signal is demodulated from the multiplex modulated wave using this. It On the other hand, the regenerated in-phase carrier is also input to the second modulation signal demodulation side and is phase shifted by π / 2 to regenerate the quadrature carrier. Then, using this,
The modulated signal of is demodulated.

Subsequently, after the first and second modulated signals are subjected to waveform equalization such as image quality improvement, the in-phase carrier is modulated with the first modulated signal to obtain a first modulated wave. , A quadrature carrier is modulated with a modulation signal to obtain a second modulated wave. Then, by combining the first modulated wave and the second modulated wave obtained in each step, the first modulated wave and the first modulated wave are combined.
It is possible to reproduce a multiplexed modulated wave in which the modulated wave and the second modulated wave having a phase difference of π / 2 are multiplexed.

An example will be described below.

[0014]

EXAMPLE In this example, an image modulated wave FV obtained by modulating an image carrier CarrV with an image signal V and an image carrier Carr.
An explanation will be given taking as an example a multiplex modulated wave F in which an orthogonal carrier wave CarrA whose phase is π / 2 different from rV and an audio modulated wave FA obtained by modulating the audio signal A are multiplexed.

In this embodiment, the modulation signal is the video signal and the audio signal, but it may be an information signal such as a character signal.
The modulation signal may be a digital signal or an analog signal. FIG. 1 is a block diagram showing an embodiment of the present invention.
Reference numeral 1 is a video carrier reproducing unit, which inputs the multiplexed modulated wave F,
It is configured to reproduce the video carrier CarrV.

Reference numeral 2 is a video modulated wave reproducing section, which inputs a multiplex modulated wave F, demodulates a video signal V from this multiplex modulated wave F, and after waveform equalizing the video signal V, the video modulated wave is generated. It is designed to play FV. The video modulated wave reproducing section 2 includes a video signal demodulating section 21 and a video signal processing section 2.
2 and a video carrier modulation section 23.

The video signal demodulation section 21 inputs the multiplex modulated wave F and the video carrier CarrV and synchronously demodulates the video signal V. Then, the video signal processing unit 22
Is designed to input a demodulated video signal V, perform signal processing for removing a ghost signal, and then output a video signal V ′. The video carrier modulation unit 23 determines the video signal V ′.
And the video carrier CarrV are input, the video carrier CarrV is modulated by the video signal V ′, and the video modulated wave FV is output to the synthesizing unit 4 described later.

Reference numeral 3 denotes an audio modulated wave reproducing unit, which inputs the multiplex modulated wave F, demodulates the audio signal A from the multiplex modulated wave F, performs signal processing on the audio signal A, and then outputs the audio modulated wave FA. Is designed to be played. The audio modulated wave reproducing unit 3 includes a first video carrier wave phase shifting unit 31, a second video carrier wave phase shifting unit 32, an audio signal demodulating unit 33, an audio signal processing unit 34, and a quadrature carrier wave modulating unit 35. It consists of

Then, the first video carrier phase shifting unit 31
Input the video carrier CarrV, and enter this video carrier Carr
Orthogonal carrier wave Carr is obtained by shifting rV by π / 2.
It is designed to play A. Audio signal demodulation unit 33
Inputs the multiple modulated wave F and the orthogonal carrier CarrA,
The audio signal A is synchronously demodulated.

The audio signal processing section 34 inputs the audio signal A, equalizes the waveform, and outputs an audio signal A '. The second video carrier phase shifting unit 32 is configured to control the video carrier Ca.
The phase shift adjustment of rrV is performed to obtain the orthogonal carrier wave CarrA ′ whose phase is π / 2 different from that of the reproduced video modulation wave FV. Therefore, even if the phase of the video modulation wave FV is deviated in the demodulation step, a multiplex modulation wave F having a phase difference of π / 2 between the video modulation wave FV and the audio modulation wave FA will be described later.
Is output from.

The quadrature carrier modulation unit 35 inputs the signal-processed voice signal A ′ and the quadrature carrier CarrA ′, modulates the quadrature carrier CarrA ′ with the voice signal A ′, and synthesizes the voice modulated wave FA, which will be described later. It is designed to output to 4. Reference numeral 4 denotes a synthesizing unit, which is configured to synthesize the input video modulation wave FV and audio modulation wave FA and reproduce the multiplex modulation wave F.

Next, the specific operation of the present invention configured as described above will be described. First, the received multiple modulated wave F
Is input to the video carrier reproduction unit 1 and is supplied to the video carrier Car.
rV is regenerated. Then, this video carrier CarrV
At the same time, the received multiple modulated wave F is input to the video signal demodulation unit 21 and is synchronously demodulated to obtain the video signal V. A ghost signal is removed from the video signal V by the video signal processing unit 22 to become a video signal V ′, which is input to the video carrier modulation unit 23.

Then, in the image carrier modulating section 23,
The video carrier wave CarrV is modulated by the video signal V ′, and the video modulation wave FV is output to the combining unit 4. On the other hand, the video carrier wave CarrV reproduced by the video carrier wave reproducing unit 1 is also input to the first video carrier wave phase shifting unit 31 and the second video carrier wave phase shifting unit 32. The video carrier wave CarrV input to the first video carrier wave phase shift unit 31 is phase-shifted by π / 2 to become the orthogonal carrier wave CarrA, and is input to the audio signal demodulation unit 33 together with the received multiplex modulated wave F. Then, the audio signal demodulation unit 33 performs synchronous demodulation to obtain the audio signal A.

The audio signal A is waveform-equalized in the audio signal processing section 34 to become an audio signal A ', which is input to the quadrature carrier modulation section 35. In addition, the second video carrier phase shifting unit 32
Adjusts the phase of the input video carrier wave CarrV, and reproduces the orthogonal carrier wave CarrA ′ having a phase difference of π / 2 with the video modulated wave FV. This orthogonal carrier CarrA '
Is input to the quadrature carrier modulation unit 35, where it is modulated with the audio signal A ′ and the modulated wave FA is output to the synthesis unit 4.

Then, the synthesizing section 4 synthesizes the input video modulation wave FV and the input modulation wave FA and outputs a multiplex modulation wave F. In this way, the multiple modulated wave F having a phase difference of π / 2 between the image modulated wave FV and the modulated wave FA is reproduced.

[0026]

According to the present invention, it is possible to easily re-multiplex each component after separating the multiple modulated waves and subjecting each separated component to processing such as ghost removal, and at the same time as the received modulated wave. The excellent effect that the multiple modulation wave can be retransmitted at the frequency is obtained.

Therefore, if the present invention is used in a television relay broadcasting facility or the like, it is possible to receive a multiple modulated wave represented by the EDTV system, remove ghost interference and retransmit.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Video carrier wave reproducing section 4 Synthesizing section 21 Video signal demodulating section 22 Video signal processing section 23 Video carrier modulating section 31 First video carrier phase shifting section 32 Second video carrier phase shifting section 33 Audio signal demodulating section 34 Audio signal processing Part 35 Quadrature carrier modulation unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 5/40 7/015

Claims (10)

[Claims] 1. A first step of modulating a in-phase carrier wave to obtain a first modulated wave, and a second step of modulating a quadrature carrier wave whose phase is π / 2 different from that of the in-phase carrier wave to obtain a second modulated wave. A step, a third step of multiplexing the first modulated wave obtained in the first step and a second modulated wave obtained in the second step, and the third step of multiplexing And a fourth step of reproducing the multiplex-modulated wave. 2. A first step of modulating a in-phase carrier wave to obtain a first modulated wave, and a second step of modulating a quadrature carrier wave whose phase is π / 2 different from that of the in-phase carrier wave to obtain a second modulated wave. A step, a third step of multiplexing the first modulated wave obtained in the first step and a second modulated wave obtained in the second step, and the third step of multiplexing And a fourth step of reproducing the multiplex modulated wave, wherein the fourth step is to reproduce the in-phase carrier from the multiplex modulated wave and remodulate the in-phase carrier. A step of obtaining the first modulated wave, and a quadrature carrier wave is regenerated from the multiplex modulated wave, and the quadrature carrier wave is re-modulated to have a phase of π with the first modulated wave obtained in the step A.
/ 2 step of obtaining a different second modulated wave, the first modulated wave obtained in the step A and the second obtained in the step B
And a step C for synthesizing the modulated wave of 1. 3. The step A includes a step of regenerating an in-phase carrier wave from the multiplex modulation wave, a demodulation step of demodulating a first modulated signal from the multiplex modulation wave using the in-phase carrier wave, and a demodulation step in this demodulation step. The method for reproducing a multiple modulated wave according to claim 2, further comprising: a step of signal-processing the first modulated signal; and a step of remodulating the in-phase carrier with the signal-processed first modulated signal. . 4. The step B includes a step of regenerating an in-phase carrier wave from the multiplex modulated wave, a step of shifting the in-phase carrier wave by π / 2 to obtain a quadrature carrier wave, and the multiplex modulated wave wave using the quadrature carrier wave. To the step of demodulating the second modulated signal, the step of signal-processing the second modulated signal, and the step of re-modulating the quadrature carrier with the signal-processed second modulated signal. The method for reproducing the multiple modulated wave according to claim 2. 5. The step B comprises a step of regenerating an in-phase carrier from the multiplex modulated wave, a step of phase-shifting the in-phase carrier by π / 2 to obtain a first quadrature carrier, and a step of recovering the first quadrature carrier. The second from the multiplex modulated wave using
The step of demodulating the second modulated signal and the step of signal processing the second modulated signal so that the phase difference between the reproduced first modulated wave and the reproduced second modulated wave becomes π / 2. And a step of remodulating the second quadrature carrier with a signal-processed second modulated signal. Two
The method for reproducing the multiple modulated wave according to. 6. The method for reproducing a multiple modulated wave according to claim 3, wherein the modulated signal is a video signal. 7. The method of reproducing a multiple modulated wave according to claim 3, wherein the modulated signal is a voice signal. 8. The method for reproducing a multiple modulated wave according to claim 3, wherein the modulated signal is a digital signal. 9. The method for reproducing a multiple modulated wave according to claim 3, wherein the modulated signal is an analog signal. 10. The method for reproducing a multiple modulated wave according to claim 3, wherein waveform equalization is performed in the step of processing the modulated signal.