JP3070506B2 - Multiplex signal reproduction apparatus, multiple signal transmission method, and multiple signal transmission apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission system, and more particularly to a multiplex signal transmission method for multiplexing and transmitting other information to a current television signal, and a generation method for multiplexing and transmitting another signal to a current television signal. The present invention relates to a device and a receiving device that receives a multiplexed transmission signal.

[0002]

2. Description of the Related Art Conventionally, as a method of multiplexing other information with a television signal, as described in Japanese Patent Application Laid-Open No. 63-36694, a quadrature carrier having a quadrature phase relationship with a video carrier is used as another information. 2. Description of the Related Art A quadrature modulation method in which a modulated signal is combined with a video carrier modulated by a video signal and transmitted is known.

[0003] On the other hand, the 1989 National Convention of the Institute of Television Engineers, pp. 307 to 308 13-12
Examination and experiment of wide aspect image transmission system, and 19
From 359 pages of the 1990 Television Society Annual Meeting 3
As described on page 60 21-1 Comparison of various widening methods from current receivers, the second generation ED
Wide aspect television screens are being studied as TVs. Various widening methods can be broadly classified into a letterbox method, a side panel method, and an intermediate method. The letterbox method related to the present invention will be briefly described with reference to FIG. FIG. 3 is a schematic diagram of a television screen in which the horizontal direction indicates the horizontal scanning direction and the vertical direction indicates the vertical scanning direction. Reference numeral 301 denotes an upper mask portion, 302 denotes a lower mask portion, and 303 denotes a television image display portion. The 16: 9 wide aspect image will be displayed in some form on the display of the current 4: 3 aspect NTSC receiver, and the letterbox method is considered as one of the display methods. The letterbox method is a method in which the left and right sides of a wide aspect image are displayed on a full screen as a display portion 303 and the upper and lower mask portions 301 and 302 are blank as shown in FIG.

[0004] One method for achieving higher definition by the letterbox method is described in the 3rd Annual Meeting of the Institute of Television Engineers of Japan in 1990.
It is described in Prototype of 21-8 letterbox type wide EDTV encoder / decoder on pages 73 to 374. According to this, vertical-
The time auxiliary signal is multiplexed and transmitted with the luminance horizontal high-definition information on the display portion, thereby improving the dynamic resolution and the horizontal resolution simultaneously with the widening.

[0005]

In the prior art as described above, the following combination of a video signal and an orthogonal multiplex signal is not described.

That is, a quadrature carrier having a quadrature phase relationship with a video carrier is modulated with other information (hereinafter, referred to as a quadrature multiplexed signal), combined with a video carrier modulated with a letterbox video signal, and transmitted. This is the modulation method.

In the quadrature modulation system, crosstalk occurs between the orthogonal multiplexed signal and the video signal due to an imbalance in the characteristics of the filters on the transmission side and the reception side, a shift in the detection axis of the receiver, and a ghost failure. In consideration of these phenomena, it is good to note that there is no problem even if the crosstalk from the orthogonal multiplexed signal in the mask portion is slightly increased when the letterbox system and the orthogonal modulation system are considered together.

An object of the present invention is to provide an optimum multiplex signal transmission method and a multiplex signal transmission apparatus when the letter box system and the quadrature modulation system are used together in consideration of the above-mentioned points of interest.
And a multiplex signal reproducing device for receiving the same.

[0009]

Means for Solving the Problems In order to achieve the above-mentioned object, the following configuration is adopted.

Means for controlling the degree of modulation of the quadrature carrier when modulating a quadrature carrier having a quadrature phase relationship with the video carrier with a quadrature multiplex signal and synthesizing with a video carrier modulated with a letterbox video signal; Means for controlling the ratio of the combined orthogonal carrier wave and modulated video carrier wave is provided, and the control is switched between the upper and lower mask portions and the display portion of the letterbox system. Also, when receiving and reproducing an orthogonal multiplex signal, a means for controlling a reproduction level obtained by demodulating the orthogonal multiplex signal or a means for controlling a level of the modulated orthogonal multiplex signal before demodulation is provided. Is switched between the upper and lower mask portions and the display portion. If the orthogonal multiplex signal is a digital signal, means for controlling the threshold level of the data strobe is provided, and the control is switched between the upper and lower mask portions and the display portion of the letterbox system.

In the present invention, since there is no problem even if the crosstalk from the orthogonal multiplex signal in the mask portion increases to some extent, the multiplex level of the orthogonal multiplex signal can be increased.

An error correction capability and an error correction capability are high, and a stable reception / reproduction operation can be performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a multiplex signal reproducing apparatus according to an embodiment of the present invention. FIG. 1 is a diagram for receiving a signal transmitted by orthogonally modulating a letterbox video signal and an orthogonal multiplexed signal.

In FIG. 1, reference numeral 101 denotes an antenna;
Is a high-frequency amplifier circuit, 103 is a frequency conversion circuit, 104 is a local oscillation circuit, 105 is a tuning control circuit, 106 is a Nyquist filter, 107 is a video detection circuit, 108 is an audio signal detection circuit, 109 is an audio signal output terminal, 110 Is a video signal output terminal, 111 is a band pass filter (hereinafter referred to as BPF
, 112 is a synchronous detection circuit, 113 is a gain control circuit, 114 is a multiplexed signal output terminal, 115 is a synchronous detection circuit, and 116 is a mask part detection circuit.

A television signal input from an antenna 101 is amplified by a high-frequency amplifier circuit 102 and frequency-converted in a frequency conversion circuit 103 by a signal from a local oscillation circuit 104. At this time, the tuning is performed by converting the signal frequency of the local oscillation circuit 104 by the tuning control circuit 105.

Next, the signal output from the frequency conversion circuit 103 is input to a Nyquist filter 106, where a necessary band is extracted. The signal output from the Nyquist filter 106 is demodulated by the video detection circuit 107,
A video signal is obtained at a video signal output terminal 110. at the same time,
An audio carrier of the television signal whose frequency has been converted to 4.5 MHz is extracted and input to the audio detection circuit 108. Then, FM detection is performed, and an audio signal is obtained at an audio signal output terminal 109.

On the other hand, the signal output from the frequency conversion circuit 103 extracts a necessary band by the BPF 111 and demodulates the orthogonal multiplexed signal by the synchronous detection circuit 112.

The demodulated video signal output from the video detection circuit 107 is of a letterbox system. The video signal is input to a synchronization detection circuit 115 to reproduce a horizontal synchronization signal, a vertical synchronization signal, and the like. Partial detection circuit 116
To obtain a timing signal indicating the upper and lower mask portions of the letterbox system. The gain control circuit 113 controls the quadrature multiplex signal demodulated by the synchronous detection circuit 112 based on the timing signal, and outputs a quadrature multiplex signal having a constant amplitude to the multiplex signal output terminal 114.

FIG. 2 is a block diagram showing an embodiment of the multiplex signal generating apparatus of the present invention for transmitting a signal received by the multiplex signal reproducing apparatus of FIG.

201 is an audio signal input terminal, 202 is FM
Modulator 203, a primary color signal input terminal, 204 a synchronization signal input terminal, 205 a matrix circuit, 206 a luminance signal processing circuit, 207 a color difference signal processing circuit, 207 a synthesis circuit, 209 a video modulator, 210 a residual A transmission VSB filter for sideband amplitude modulation, 211 is an orthogonal multiplexed signal input terminal, 212 is a video signal carrier generator, 213 is a phase shifter,
214 is a modulator for orthogonal multiplexed signals, 215 is a gain adjustment circuit, 216 is an equalizer, 217 and 218 are adders, 2
19 is an upconverter for tuning, 220 is an antenna,
221 is a mask part detection circuit.

The audio signal from the audio signal input terminal 201 is FM-modulated in an FM modulator 202. The RGB three primary color signals input from the primary color signal input terminal 203 are separated into a luminance signal and a color difference signal by a matrix circuit 205 and processed by a luminance signal processing circuit 206 and a color difference signal processing circuit 207, respectively. The synchronizing signal is synthesized by the synthesizing circuit 208 at the timing of the synchronizing signal to obtain a letterbox video signal. The carrier from the video signal carrier generator 212 is converted to the video modulator 20 by this video signal.
9 and the transmission VSB filter 210 limits the band to the television broadcast band. Thereafter, the adder 218
Then, the modulated sound wave is added, the channel is selected by the up-converter 219 and transmitted from the antenna 220.

On the other hand, a quadrature multiplex signal to be multiplexed is applied to an input terminal 211, and a video signal carrier wave shifted by 90 degrees through a phase shifter 213 with this signal is modulated by a modulator 214 to obtain a quadrature modulated signal. . Here, based on the synchronization signal input from the synchronization signal input terminal 204, the timing indicating the upper and lower mask portions of the letterbox system is determined by the mask portion detection circuit 221.
The gain adjustment circuit 215 switches the gain of the quadrature modulation signal between the mask portion and the display portion as a control signal.
The output of the gain adjustment circuit 215 corrects the frequency characteristic by an equalizer 216 having the inverse characteristic of the Nyquist filter of the video signal IF, and adds the output to the carrier modulated by the video signal by the adder 217. As a result, the carrier for video is modulated in an orthogonal relationship with the video signal of the letterbox system and the orthogonal multiplexed signal.

Here, the gain control circuit 113 of FIG.
The gain adjustment circuit 215 operates as follows.

Since there is no problem even if the crosstalk from the orthogonal multiplex signal in the mask portion increases slightly, the gain adjustment circuit 215 on the multiplex signal generator side increases the multiplex level of the orthogonal multiplex signal. In response to this, on the multiplex signal reproducing device side, the gain control circuit 113 reduces the orthogonal multiplex signal gain in the mask portion and controls the gain so as to have a constant amplitude.

Thus, when both the letterbox system and the quadrature modulation system are used, multiplexing optimal for both systems can be performed.

In the embodiment shown in FIG. 1, there is an effect that the operating frequency band of the gain control circuit 113 can be set to the baseband band.

In the embodiment shown in FIG. 2, since the gain adjustment circuit 215 is arranged at the subsequent stage of the modulator 214, there is an effect that the operation of the modulator 214 is not burdened.

FIG. 4 is a block diagram showing an embodiment of another multiplex signal reproducing apparatus according to the present invention. FIG. 4 is a diagram for receiving a signal transmitted by orthogonally modulating a letterbox video signal and an orthogonal multiplexed signal.

The same reference numerals as those in FIG. 1 indicate the same functions,
401 is a gain control circuit. In FIG. 4, the gain control is performed in the intermediate frequency band, and the control method is the same as in FIG.

In the embodiment shown in FIG. 4, the gain control circuit 401 is arranged in front of the BPF 111, so that the effect of out-of-band noise generated in the gain control circuit 401 can be eliminated by the BPF 111.

FIG. 5 is a block diagram showing an embodiment of another multiplex signal reproducing apparatus according to the present invention. FIG. 5 is a diagram for receiving a signal transmitted by orthogonally modulating a letterbox video signal and an orthogonal multiplexed signal.

The same reference numerals as those in FIG. 1 indicate the same functions.
501 is a gain control circuit. In FIG. 5, the gain control is performed in the intermediate frequency band, and the control method is the same as in FIG.

In the embodiment shown in FIG. 4, since the gain control circuit 501 is disposed after the BPF 111, the operation of the gain control circuit 501 does not become unstable due to the influence of out-of-band noise.

FIG. 6 is a block diagram showing an embodiment of another multiplex signal reproducing apparatus according to the present invention. FIG. 6 shows the reception of a signal transmitted by orthogonally modulating a letterbox video signal and a quadrature multiplexed signal digitally encoded with three values.

The components having the same reference numerals as those in FIG.
601 and 602 are comparison circuits, 603 and 604 are reference signal generation circuits, and 605 is a digital signal decoding circuit.

Outputs of the synchronous detection circuit 112 are +1, 0,-
In order to discriminate between the two, the comparator circuit 601 determines that the value larger than the output of the reference signal generation circuit 603 is +1;
A value smaller than the output of the reference signal generation circuit 604 is determined as -1 according to 02, and a decoding circuit 605 performs data strobe and digital signal decoding processing to detect a ternary signal. The reference signal generation circuits 603 and 604 are controlled by the output of the mask portion detection circuit 116, and change the discrimination level between the letterbox type mask portion and the display portion.
The change in the discrimination level is controlled so as to always be an intermediate level between +1 and 0 and between 0 and -1.

The embodiment shown in FIG. 6 has an effect that the digitally encoded orthogonal multiplex signal can be identified at an optimum level.
Although the three-valued digital signal is shown in the embodiment of FIG. 6, in general, in the case of an n-valued digital signal, n-valued digital signal is used.
If one comparison circuit and a reference signal generation circuit are provided, the configuration can be the same as in the case of FIG.

FIG. 7 is a block diagram showing another embodiment of the multiplex signal generator of the present invention.

Those having the same reference numerals as those in FIG. 2 indicate the same functions,
701 is a gain adjustment circuit.

In FIG. 7, the gain is adjusted in the base band, and the adjustment is performed in the same manner as in FIG.

In the embodiment shown in FIG. 7, there is an effect that the operating frequency band of the gain adjustment circuit 701 can be set to the base band.

FIG. 8 is a block diagram showing another embodiment of the multiplex signal generator of the present invention.

The same reference numerals as those in FIG. 2 indicate the same functions,
801 is a gain adjustment circuit.

In FIG. 8, the gain adjustment is performed after the equalizer 216, and the manner of adjustment is the same as in FIG.

In the embodiment shown in FIG. 8, since the gain adjustment circuit 801 is arranged at the subsequent stage of the equalizer 216, the operation of the gain adjustment circuit 801 does not become unstable due to the influence of out-of-band noise.

[0046]

According to the present invention, a quadrature modulation method for modulating a quadrature carrier having a quadrature phase relationship with a video carrier with a quadrature multiplex signal, combining the modulated carrier with a video carrier modulated with a letterbox video signal, and transmitting the resultant signal. When the letterbox method and the quadrature modulation method are used in combination as described above, attention is paid to the fact that crosstalk occurs between the letterbox method video signal and the orthogonal multiplexed signal, and the following effects are obtained.

Since there is no problem even if the crosstalk from the orthogonal multiplex signal in the mask portion slightly increases, the multiplex level of the orthogonal multiplex signal can be increased. In response, the receiving side controls the gain so as to reduce the orthogonal multiplexed signal gain in the mask portion so that the amplitude becomes constant. Thus, there is an effect that an optimal multiplex signal transmission method, a multiplex signal transmission device thereof, and a multiplex signal reproduction device receiving the same can be configured.

[Brief description of the drawings]

FIG. 1 is a block diagram of a multiplex signal reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a multiplexed signal generator showing one embodiment of the present invention.

FIG. 3 is a schematic diagram of a letter box type screen.

FIG. 4 is a block diagram of a multiplex signal reproducing apparatus according to an embodiment of the present invention.

FIG. 5 is a block diagram of a multiplex signal reproducing apparatus according to an embodiment of the present invention.

FIG. 6 is a block diagram of a multiplex signal reproducing apparatus according to an embodiment of the present invention.

FIG. 7 is a block diagram of a multiplexed signal generator showing one embodiment of the present invention.

FIG. 8 is a block diagram of a multiplexed signal generator showing one embodiment of the present invention.

[Explanation of symbols]

 113: gain control circuit, 115: synchronization detection circuit, 116: mask part detection circuit, 215: gain adjustment circuit, 221: mask part detection circuit, 401: gain control circuit, 501: gain control circuit, 601: comparison circuit, 602 … Comparison circuit, 603… reference signal generation circuit, 604… reference signal generation circuit, 701… gain adjustment circuit, 801… gain adjustment circuit.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazumio Nakagawa 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within Hitachi Media Media Research Laboratories (56) References JP-A-63-240195 (JP, A) JP-A-62-98883 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N ⁷ /025-7/088 H04J 11 / 00

Claims (9)

(57) [Claims] (1)4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A transmission signal in which another signal is multiplexed and transmitted by a wave, and
The transmission signal sets the amplitude level of the another signal to the upper mask unit.
Minutes or the period of the lower mask part is the display part
Is multiplexed and transmitted as a multiplex amplitude greater than the period
Or said video carrier modulated with said another signal
The amplitude of the carrier orthogonal to the period of the upper mask portion or
Indicates that the period of the lower mask portion is longer than the period of the display portion.
Receives and reproduces transmission signals that are multiplexed and transmitted as multiple amplitudes
Multiplex signal reproducing device,  The multiplex transmission is performed by detecting the orthogonal carrier.
Synchronous detection means for outputting a signal ofThe display portion and the upper mask portion or the lower mask
Part and outputs a timing signal to identify the detected part.
Detecting means to force; Using the timing signal output by the detection means
The period of the upper mask portion or the lower mask portion.
The period is a gain smaller than the period of the display part, and
The amplitude of another signal output from the synchronous detection means is set to a constant amplitude.
Variable gain means,  A multiplexed signal reproducing device comprising: (2)4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A transmission signal in which another signal is multiplexed and transmitted by a wave, and
The transmission signal sets the amplitude level of the another signal to the upper mask unit.
Minutes or the period of the lower mask part is the display part
Is multiplexed and transmitted as a multiplex amplitude greater than the period
Or said video carrier modulated with said another signal
Carrier orthogonal to In the period of the upper mask portion or
Indicates that the period of the lower mask portion is longer than the period of the display portion.
Receives and reproduces transmission signals that are multiplexed and transmitted as multiple amplitudes
Multiplex signal reproducing device,  The multiplex transmission is performed by detecting the orthogonal carrier.
Synchronous detection means for outputting a signal ofThe display portion and the upper mask portion or the lower mask
Part and outputs a timing signal to identify the detected part.
Detecting means to force; Using the timing signal output by the detection means
The period of the upper mask portion or the lower mask portion.
The period is a gain smaller than the period of the display part, and
The amplitude of the signal input to the synchronous detection means is fixed
Variable gain means;  A multiplexed signal reproducing device comprising: (3)4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A transmission signal in which another signal is multiplexed and transmitted by a wave, and
The transmission signal sets the amplitude level of the another signal to the upper mask unit.
Minutes or the period of the lower mask part is the display part
Is multiplexed and transmitted as a multiplex amplitude greater than the period
Or said video carrier modulated with said another signal
The amplitude of the carrier orthogonal to the period of the upper mask portion or
Indicates that the period of the lower mask portion is longer than the period of the display portion.
Receives and reproduces transmission signals that are multiplexed and transmitted as multiple amplitudes
Multiplex signal reproducing device, The transmission signal And receive it as a reception signal.
To extract the multiplexed frequency band of the another signal from the
Ruta means,The display portion and the upper mask portion or the lower mask
Part and outputs a timing signal to identify the detected part.
Detecting means to force; Using the timing signal output by the detection means
The period of the upper mask portion or the lower mask portion.
The period is a gain smaller than the period of the display part, and
Variable to make the amplitude of the output signal of the filter means constant
Gain means; Output signal of the variable gain meansToDetect with the orthogonal carrier
Synchronization detection to output another signal multiplexed by
A multiplex signal reproducing device, comprising: wave means; (4)4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A transmission signal in which another signal is multiplexed and transmitted by a wave, and
The transmission signal sets the amplitude level of the another signal to the upper mask unit.
Minutes or the period of the lower mask part is the display part
Is multiplexed and transmitted as a multiplex amplitude greater than the period
Or said video carrier modulated with said another signal
The amplitude of the carrier orthogonal to the period of the upper mask portion or
Indicates that the period of the lower mask portion is longer than the period of the display portion.
Receives and reproduces transmission signals that are multiplexed and transmitted as multiple amplitudes
Multiplex signal reproducing device, The display portion and the upper mask portion or the lower mask portion
Detects minute and outputs timing signal to identify detected part
Detecting means for  The multiplex transmission is performed by detecting the orthogonal carrier.
A synchronous detection means for outputting a signal of the following, and another signal which is an output of the synchronous detection means,For input signal
A first plurality of reference levels, the reference levels being smaller than for the input signal;
Second plurality of reference levels for the input signalComparison hand with
A converting means for converting the digital signal into binary or more digital signals in a stage;Using the timing signal output by the detection means
The period of the display portion is the second plurality of reference levels.
And the period of the upper mask portion or the lower mask portion
Period is set to be the first plurality of reference levels.
Switching means for changing,  A multiplexed signal reproducing device comprising: (5)4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Minutes Upper mask part and lower mask part masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
Multiplex signal transmission method for multiplex transmission of another signal
hand,  The amplitude level of said another signal,PreviousPeriod of the written mask part
Alternatively, the period of the lower mask portion is equal to the period of the display portion.
Multiplex transmission with a larger multiplex amplitude.
Multiplex signal transmission method. 6.4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A multiplex signal transmission method that multiplexes another signal with waves
So,  A carrier orthogonal to the video carrier modulated by the another signal.
The amplitude of the transmission,PreviousThe period of the above mask or the lower mask
The period of the disk portion is longer than the period of the display portion.
Multiplex signal transmission characterized by multiple transmission as width
Method. 7.4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A multiplex signal transmission device that multiplexes and transmits another signal using waves.
hand,  The amplitude level of said another signal,PreviousPeriod of the written mask part
Alternatively, the period of the lower mask portion is equal to the period of the display portion.
Larger multiple amplitudePossibleA multiplex signal transmission device, comprising: a variable gain means; Claim 8.4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A multiplex signal transmission device that multiplexes and transmits another signal using waves.
hand,  A carrier orthogonal to the video carrier modulated by the another signal.
The amplitude of the transmission,PreviousThe period of the above mask or the lower mask
The period of the disk portion is longer than the period of the display portion.
WidthStrangeA multiplexing signal transmission device, comprising: 9.4: 3 Aspect with vestigial sideband amplitude modulation
Table with a wide-aspect image in the center of the
And the upper and lower parts of the 4: 3 aspect screen
Upper mask part and lower mask part where parts are masked with a single color
And a carrier orthogonal to the video carrier of the video signal composed of
A multiplex signal transmission device that multiplexes and transmits another signal using waves.
hand,  A carrier orthogonal to the video carrier modulated by the another signal.
Extracting the multiplexed frequency band of said another signal from the transmission
Filter means, and an amplitude level of an output signal of the filter means.,PreviousWriting
The period of the mask portion or the period of the lower mask
Multiple amplitude greater than the periodPossibleVariable gain means
And a multiplex signal transmission device, comprising: