JP3012656B2 - MUSE signal processing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MUSE television signal receiving apparatus.

Conventional technology The specification of MUSE signal is NHK Technical Research, Showa 62. "Development of MUSE"
Is shown in FIG. 3 shows a transmission signal form of the MUSE signal.

When FM transmission of a MUSE signal is performed using a broadcasting satellite, the MUSE encoder performs S / N by transmitting a high frequency component of a video signal.
In order to compensate for the deterioration of the image signal, pre-emphasis processing for increasing the gain of the high frequency component is performed only on the video signal portions indicated as C video and Y video in FIG.
The signal subjected to the pre-emphasis processing causes considerable overshoot and undershoot with respect to the original video signal amplitude, but fits into the satellite broadcasting band by performing non-linear processing to suppress the overshoot and undershoot. Signal amplitude. 4th
The figure shows the relationship between pre-emphasis processing, non-linear processing, and signal amplitude. As shown in FIG. 4 (c), the FM specification MUSE signal is subjected to pre-emphasis processing (FIG. 4b), and includes an overshoot and an undershoot due to the pre-emphasis, and the difference between the black level and the white level of the video signal. It has almost twice the amplitude. On the other hand, when the MUSE signal is transmitted by AM, pre-emphasis processing and non-linear processing are not performed. Therefore, as shown in FIG. 4A, the difference between the black level and the white level of the video signal of the MUSE signal (original signal) of the AM specification has the maximum amplitude.

Information on whether the MUSE signal output from the encoder is of the AM specification or the FM specification is multiplexed in a period shown as a control signal in FIG. The control signal has 32 bits. If the 20th bit is "0", the FM specification MU
This is an SE signal, and if it is "1", it is an AM specification MUSE signal.

FIG. 5 shows a configuration diagram of a conventional MUSE signal processing device, and reference numeral 10 denotes a MUSE signal input terminal. 20 is an A / D conversion circuit that converts the MUSE signal to a digital signal, 30 is a gain adjustment circuit that adjusts the level of the input signal according to the input signal specifications, and 40 is a synchronizing signal pattern of the MUSE signal and outputs an internal synchronizing signal. The synchronization signal detection circuit 50, which is a control signal detection timing signal synchronized with the input signal and the MUSE
A timing signal generation circuit that outputs a processing timing signal, 60 is a control signal detection circuit that detects an AM / FM control signal and a MUSE processing control signal from a control signal portion of the MUSE signal, and 70 is a pre-emphasis performed by an encoder. A de-emphasis circuit that performs an inverse process, 80 is a switching circuit that switches and outputs the output of the gain adjustment circuit 30 and the output of the de-emphasis circuit 70, and 90 is an MU.
A MUSE processing circuit that decodes the SE signal and outputs at least a luminance signal and a color difference signal that are video signals.
A D / A conversion circuit 110 converts an output of the E processing circuit 90 into an analog signal, and 110 is a video signal output terminal.

The conventional MUSE signal processing device configured as described above operates as follows.

When the MUSE signal is input to the MUSE signal input terminal 10, the A / D
The conversion circuit 20 performs A / D conversion of the input signal, and
0, synchronization signal detection circuit 40, control signal detection circuit 60
Output to The synchronization signal detection circuit 40 detects a frame pulse signal pattern and a horizontal synchronization signal pattern which are synchronization signal patterns of the MUSE signal, and outputs an internal synchronization signal to the timing signal generation circuit 50. Timing signal generation circuit
50 generates a control signal detection timing signal and a MUSE processing timing signal synchronized with the input signal based on the internal synchronization signal from the synchronization signal detection circuit 40, and sends them to the control signal detection circuit 60 and the MUSE processing circuit 90, respectively. Output. The control signal detection circuit 60 uses a control signal detection timing signal corresponding to the control signal portion of the input signal from the timing signal generation circuit 50.
Detects the control signal of the MUSE signal and outputs the AM / FM control signal for discriminating between the MUSE signal of the AM specification and the MUSE signal of the FM specification to the gain adjustment circuit 30 and the switching circuit 80. A control signal for MUSE processing such as a signal is output to the MUSE processing circuit. Gain adjustment circuit 30 is AM specification MUSE signal and FM specification
In order to make the level of the video signal portion of the MUSE signal uniform, when the input signal is an FM specification MUSE signal by the FM / AM control signal from the control signal detection circuit 60, the gain thereof is approximately twice as large as the AM specification MUSE signal. The de-emphasis circuit 70 performs non-linear return processing which is the reverse processing of the nonlinear processing performed by the encoder on the output signal of the gain adjustment circuit 30, and de-emphasis processing which is the reverse processing of the pre-emphasis processing. The switching circuit 80 is a gain adjustment circuit when the input signal is an AM specification MUSE signal according to the AM / FM control signal from the control signal detection circuit 60.
The output of 30 is selected, and if the input signal is an FM specification MUSE signal, the output of the de-emphasis circuit 70 is selected and output to the MUSE processing circuit 90. The MUSE processing circuit 90 decodes the output signal of the switching circuit 80 based on the MUSE processing timing signal from the timing signal generation circuit 50 and the MUSE processing control signal from the control signal detection circuit 60, and outputs a video signal. The D / A conversion circuit 100 performs D / A conversion on the video signal output from the MUSE processing circuit 90, and outputs the video signal to the video signal output terminal 110.

The MUSE signal transmission method using a broadcast satellite is an FM transmission method. For example, when recording an FM-transmitted MUSE signal on a recording / reproducing device such as a VTR, an FM transmission MUSE signal, which is a signal obtained by FM demodulation of an incoming transmission signal in a tuner, can be directly recorded, or a conventional MUSE signal processing method can be used. It is easy to think of a method of recording the output of the de-emphasis circuit of the device.

As shown in FIG. 4 (c), the FM specification MUSE signal includes overshoots and undershoots larger than the original video signal amplitude. The amplitude of the video signal portion is substantially equal to or less than one half of the allowable input signal amplitude of the recording / reproducing device, and the S / N of the video signal is significantly deteriorated during recording.

The de-emphasis circuit is a circuit for restoring the FM specification MUSE signal to the original video signal as shown in FIG. Therefore, when recording the output of the de-emphasis circuit, the video signal amplitude becomes the permissible input signal amplitude of the recording / reproducing device, and the S / N of the video signal at the time of recording is improved compared to the case where the FM specification MUSE signal is recorded as it is. Is done.

However, in the configuration of the conventional MUSE signal processing device,
Since the de-emphasis processing is performed on the portion other than the video signal portion, the sync signal pattern portion and the control signal portion are deteriorated. In addition, it is AM specification MUSE signal or FM
The control signal to determine whether it is a MUSE signal is FM
It remains the specification.

Therefore, when the output of the de-emphasis circuit is recorded,
When the playback signal is input to a conventional MUSE signal processor,
There is a problem that the synchronization detection circuit cannot detect the synchronization signal pattern, or the control signal detection circuit erroneously detects the control signal. Further, since the conventional MUSE signal processing device processes the reproduced signal as a MUSE signal of FM specification, the video signal after deemphasis processing is further subjected to deemphasis processing.
As in the case where the de-emphasis processing is performed on the MUSE signal, there is a problem that the gain of the high frequency component of the video signal is reduced and a normal video signal output cannot be obtained.

The present invention has been made in view of the problems of the related art, when inputting an FM-specification MUSE signal to a recording / reproducing device such as a VTR, using a signal obtained by performing de-emphasis processing only on a video signal portion,
It is an object of the present invention to provide a MUSE signal processing device which replaces a control signal portion for discriminating between an AM-specification MUSE signal and an FM-specification MUSE signal and converts the signal into a complete AM-specification MUSE signal.

Means for Solving the Problems The present invention provides a gain adjustment circuit that adjusts the level of an input signal according to the specification of an input signal, a synchronization signal detection circuit that detects a synchronization signal from the input signal, and a timing signal synchronized with the input signal. A timing signal generating circuit for outputting, a control signal detecting circuit for detecting a control signal from an input signal, a de-emphasis circuit for performing reverse processing of pre-emphasis processing on an output signal of the gain adjusting circuit, and an output signal of the gain adjusting circuit and a de-emphasis circuit. A switching circuit for switching between the output signal of the emphasis circuit and a control signal replacement circuit for replacing a control signal portion of the output signal of the switching circuit, and if the input signal is an FM-specification MUSE signal, de-emphasis processing is further performed. The bit indicating FM / AM is replaced with the AM specification by the control signal replacement circuit, and the AM specification MUS
It is characterized in that it is converted into an E signal and output.

The present invention includes overshoot due to the above-described configuration.
When the FM specification MUSE signal is input, the AM / FM control signal is detected, the level of the input signal is approximately doubled with the AM specification MUSE signal by the AM / FM control signal, and the de-emphasis processing is performed. Output to the switching circuit, switch between the output of the de-emphasis circuit and the output of the gain adjustment circuit, and output the signal that has been subjected to de-emphasis processing only to the video signal part to the control signal replacement circuit, FM specification
Outputs the MUSE signal as a complete AM specification MUSE signal.

Examples Hereinafter, examples of the present invention will be described.

FIG. 1 shows a configuration diagram of a MUSE signal processing device according to a first embodiment of the present invention. In FIG. 1, the same components as those in the conventional example shown in FIG. In the figure, reference numeral 51 denotes a control signal detection circuit synchronized with an input signal, a control signal replacement timing signal, a switching timing signal, and a MUSE processing timing signal.
60, control signal replacement circuit 120, switching circuit 81 and M
A timing signal generation circuit that outputs to the USE signal processing circuit 90, 81 is a switching circuit that switches and outputs the output of the gain adjustment circuit 30 and the output of the de-emphasis circuit 70, and 120 replaces the control signal portion of the output of the switching circuit 81. 130 is a second D / A conversion circuit that converts the output of the control signal replacement circuit into an analog signal, 140 is A
M specification MUSE signal output terminal. 101 performs the same operation as the D / A conversion circuit 100 in FIG. 5, but in FIG.
It is called a conversion circuit.

In the MUSE signal processing device of this embodiment configured as described above, when the MUSE signal is input to the MUSE signal input terminal 10, the A / D conversion circuit 20 performs A / D conversion of the input signal and adjusts the gain. The signal is output to the circuit 30, the synchronization signal detection circuit 40, and the control signal detection circuit 60.

The synchronization signal detection circuit 40 detects a frame pulse signal and a horizontal synchronization signal which are synchronization signal patterns of the MUSE signal, and outputs an internal synchronization signal to the timing signal generation circuit 51.

The timing signal generation circuit 51 generates a control signal detection timing signal, a control signal replacement timing signal, and a MUSE processing timing signal synchronized with the input signal based on the internal synchronization signal from the synchronization signal detection circuit 40, and outputs each of them. Control signal detection circuit 60,
Output to the control signal replacement circuit 120 and the MUSE processing circuit 90. The control signal detection circuit 60 detects the control signal of the MUSE signal based on the control signal detection timing signal supplied from the timing signal generation circuit 51, and discriminates between the AM specification MUSE signal and the FM specification MUSE signal.
/ FM control signal to gain adjustment circuit 30 and switching circuit 81
And outputs a control signal for MUSE processing such as a motion vector control signal and a sub-sample phase control signal to the MUSE processing circuit 90.

The gain adjustment circuit 30 adjusts the gain when the input signal is the FM specification MUSE signal by the FM / AM control signal from the control signal detection circuit 60 in order to match the level of the video signal section of the AM specification MUSE signal and the FM specification MUSE signal. It is approximately twice as large as the AM specification MUSE signal.

The de-emphasis circuit 70 performs non-linear return processing which is the reverse processing of the nonlinear processing performed by the encoder on the output signal of the gain adjustment circuit 30, and de-emphasis processing which is the reverse processing of the pre-emphasis processing. The switching circuit 81 is controlled by an AM / FM control signal from the control signal detection circuit 60 and a switching timing signal corresponding to the video signal portion from the timing signal generation circuit 51.
If the input signal is an AM specification MUSE signal, select the output of the gain adjustment circuit 30.If the input signal is an FM specification MUSE signal, select the output of the de-emphasis circuit 70 only for the video signal part of the input signal. Select the output of the adjustment circuit 30,
It outputs to the MUSE processing circuit 90 and the control signal replacement circuit 120. The MUSE processing circuit 90 is controlled by the MUSE processing control signal from the control signal detection circuit 60 and the MUSE processing timing signal from the timing signal generation circuit 51, decodes the MUSE signal output from the switching circuit 81, and decodes the original MUSE signal. It outputs video signals of high-definition television signals.
The first D / A conversion circuit 101 performs D / A conversion on the video signal output from the MUSE processing circuit 90 and outputs it to the video signal output terminal 110.

On the other hand, the control signal replacement circuit 120 replaces the 20th bit of the control signal with "1" by a control signal replacement timing signal corresponding to the control signal portion of the output signal of the switching circuit 81 from the timing signal generation circuit 51. And output. The second D / A conversion circuit 130 performs D / A conversion on the output of the control signal replacement circuit 120, and outputs
Output to SE signal output terminal 140.

As described above, according to the first embodiment, the FM specification MUSE
When the signal is input, the level of the video signal part is AM specification
A gain adjustment circuit 30 for aligning with the MUSE signal, a de-emphasis circuit 70 for restoring the video signal before pre-emphasis processing without overshoot or undershoot,
A switching circuit 81 for switching between processes other than the video signal portion subjected to the pre-emphasis process and the video signal portion not subjected to the pre-emphasis process, and the AM specification MUSE signal and FM
By providing a control signal replacement circuit 120 that replaces the 20th bit of the control signal that determines the specification MUSE signal, the FM specification MUSE signal is converted to a complete AM specification MUSE signal without overshoot or undershoot. Can be.

FIG. 2 shows a configuration diagram of a MUSE signal processing device according to a second embodiment of the present invention. In FIG. 2, the same elements as those in the first embodiment shown in FIG. In the figure, reference numeral 52 denotes a control signal detection timing signal, a control signal replacement timing signal, a switching timing signal, and a MU synchronized with an input signal.
A timing signal generating circuit that generates a timing signal for SE processing and a timing signal for recording and reproduction, and outputs each to the control signal detection circuit 60, the control signal replacement circuit 120, the switching circuit 81, the MUSE processing circuit 90, and the recording and reproduction circuit 150, 150 is a recording / reproducing circuit capable of recording / reproducing the output of 120 of the second D / A conversion circuit, and 160 is a reproducing AM specification MUS
E signal output terminal.

In the MUSE signal processing device of this embodiment configured as described above, when the MUSE signal is input to the MUSE signal input terminal 10, the A / D conversion circuit 20 performs A / D conversion of the input signal and adjusts the gain. The signal is output to the circuit 30, the synchronization signal detection circuit 40, and the control signal detection circuit 60. The synchronization signal detection circuit 40 detects a frame pulse signal and a horizontal synchronization signal which are synchronization signal patterns of the MUSE signal, and outputs an internal synchronization signal to the timing signal generation circuit 52. The timing signal generation circuit 52
Generates a control signal detection timing signal, control signal replacement timing signal, MUSE processing timing signal, and recording / playback timing signal synchronized with the input signal based on the internal synchronization signal from the synchronization signal detection circuit 40, and controls each of them. The signal is output to the signal detection circuit 60, the control signal replacement circuit 120, the MUSE processing circuit 90, and the recording / reproducing circuit 150. Control signal detection circuit 60
Detects the control signal of the MUSE signal by the control signal detection timing signal corresponding to the control signal portion of the input signal from the timing signal generation circuit 52,
AM / FM that distinguishes between MUSE signal for AM specification and MUSE signal for FM specification
The control signal is output to the gain adjustment circuit 30 and the switching circuit 81, and a control signal for MUSE processing such as a motion vector control signal and a sub-sample phase control signal is output to the MUSE processing circuit. Gain adjustment circuit 30 is AM specification
If the input signal is an FM-specific MUSE signal by the FM / AM control signal from the control signal detection circuit 60, the gain of the MUSE signal and the FM-specific MUSE signal are adjusted to approximately the same level as the AM-specific MUSE signal in order to match the levels of the video signal portions of the MUSE signal Doubled. The de-emphasis circuit 70 performs non-linear return processing which is the reverse processing of the non-linear processing performed by the encoder on the output signal of the gain adjustment circuit 30, and de-emphasis processing which is the reverse processing of the pre-emphasis processing. Switching circuit
81 is an AM / FM control signal from the control signal detection circuit 60 and a switching timing signal corresponding to the video signal portion from the timing signal generation circuit 52, and the gain adjustment circuit 30 Select the output, and if the input signal is an FM-specification MUSE signal, select the output of the de-emphasis circuit 70 only for the video signal part of the input signal, and select the output of the gain adjustment circuit 30 for the other parts. Output to the signal replacement circuit 120. The MUSE processing circuit 90 is controlled by the MUSE processing control signal from the control signal detection circuit 60 and the MUSE processing timing signal from the timing signal generation circuit 52, decodes the MUSE signal output from the switching circuit 81, and decodes the original MUSE signal. It outputs video signals of high-definition television signals. 1D
The / A conversion circuit 101 performs D / A conversion of the video signal output from the MUSE processing circuit 90 and outputs it to the video signal output terminal 110. On the other hand, the control signal replacement circuit 120 replaces the 20th bit of the control signal with “1” by the control signal replacement timing signal corresponding to the control signal portion of the output signal of the selection circuit 81 from the timing signal generation circuit 52. Output. The second D / A conversion circuit 130 performs D / A conversion on the output of the control signal replacement circuit 120 and outputs it to the recording / reproducing circuit 150.

The recording / reproducing circuit 150 is controlled by a recording / reproducing timing signal from the timing signal generating circuit 52, and can record or reproduce the output of the second D / A conversion circuit 130. Output to terminal 160.

As described above, according to the second embodiment, the MUSE signal processing circuit includes a recording / reproducing circuit therein, converts an FM-specific MUSE signal into an AM-specific MUSE signal, records the signal, and reproduces the signal as an AM-specific MUSE signal. It is possible to

Effects of the Invention As described above, according to the present invention, it is possible to convert an FM-specific MUSE signal into a complete AM-specific MUSE signal. Therefore, when recording the MUSE signal on a recording / reproducing device such as a VTR,
An FM transmission MUSE signal, which is an incoming transmission signal, can be converted into an AM transmission MUSE signal and recorded. Since the AM specification MUSE signal does not include overshoot or undershoot due to pre-emphasis, if the signal amplitude is the same, the S / N of the video signal at the time of recording / reproduction can be greatly improved. Further, since no de-emphasis processing is performed on portions other than the video signal portion, the control signal portion and the synchronization signal pattern do not deteriorate. Furthermore, the FM specification of the control signal has been replaced with the AM specification, making it a complete AM specification MUSE signal. as a result,
The MUSE signal output of the AM specification of the MUSE signal processing device of the present invention is recorded in a recording / reproducing device, and the reproduced signal is recorded in a MUSE signal equivalent to the present invention.
Even when the signal is input to the signal processing device, a video signal with a good S / N can be restored without performing any special operation on the MUSE signal processing device, and the practical effect is large.

[Brief description of the drawings]

FIG. 1 is a block diagram of a MUSE signal processing device according to a first embodiment of the present invention, FIG. 2 is a block diagram of a MUSE signal processing device according to another embodiment of the present invention, and FIG.
FIG. 4 is an explanatory diagram showing a signal transmission signal format, FIG. 4 is an explanatory diagram showing a change in signal amplitude in pre-emphasis and nonlinear processing, and FIG. 5 is a block diagram of a conventional MUSE signal processing device. 10 MUSE signal input terminal, 20 A / D conversion circuit, 30
Gain adjustment circuit, 40 …… Synchronous signal detection circuit, 50,51 ……
Timing signal generation circuit, 60: Control signal detection circuit, 70: Deemphasis circuit, 80, 81: Switching circuit, 120: Control signal replacement circuit, 130: 2nd D / A
Circuit, 140: MUSE signal output terminal for AM specification, 150: Recording / reproduction circuit, 160: MUSE signal output terminal for reproduction AM specification

Continued on the front page (72) Inventor Mitsuo Isobe 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Yuichi Ninomiya 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Technology Research Association (72) Inventor Seiichi Koshi 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Research Institute of Broadcasting Technology (56) References JP-A-1-136486 (JP, A) (58) Fields surveyed ( Int.Cl. ⁷ , DB name) H04N 7/015

Claims (4)

(57) [Claims] 1. FM specification performing pre-emphasis processing
MUSE signal or AM specification MU without pre-emphasis processing
Any one of the SE signals as an input, at least a gain adjustment circuit that adjusts the level of the input signal according to the specification of the input signal, a synchronization signal detection circuit that detects a synchronization signal from the input signal, and a timing synchronized with the input signal A timing signal generation circuit that outputs a signal, a control signal detection circuit that detects a control signal from the input signal, and a de-emphasis circuit that performs a de-emphasis process that is a reverse process of the pre-emphasis process on an output signal of the gain adjustment circuit. A switching circuit for switching between an output signal of the gain adjustment circuit and an output signal of the de-emphasis circuit,
A control signal replacement circuit that replaces a control signal portion of an output signal of the switching circuit.If the input signal is an FM specification MUSE signal, a deemphasis process is performed, and the control signal replacement circuit further performs
A MUSE signal processing device wherein a bit indicating FM / AM is replaced with an AM specification, converted to an AM specification MUSE signal, and output. 2. FM specification performing pre-emphasis processing
MUSE signal or AM specification MU without pre-emphasis processing
Any one of the SE signals is input, at least, a gain adjustment circuit that adjusts the level of the input signal according to the specification of the input signal, a synchronization signal detection circuit that detects a synchronization signal from the input signal, and a signal synchronized with the input signal. A timing signal generation circuit for outputting a timing signal; a control signal detection circuit for detecting a control signal from the input signal; and a de-emphasis circuit for performing a de-emphasis process, which is a reverse process of the pre-emphasis process, on an output signal of the gain adjustment circuit. A switching circuit that switches between an output signal of the gain adjustment circuit and an output signal of the de-emphasis circuit, a control signal replacement circuit that replaces a control signal portion of the output signal of the switching circuit, and a recording / reproducing circuit. If the input signal is an FM-specification MUSE signal, de-emphasis processing is performed. In addition the control signal substitution circuit and
A MUSE signal processing device characterized in that bits indicating FM / AM are replaced with AM specifications, converted into AM specification MUSE signals and recorded. 3. The MUSE signal processing device according to claim 1, wherein the gain adjustment circuit is controlled by a control signal detected by a control signal detection circuit. 4. The MUSE signal processing device according to claim 1, wherein the switching circuit is controlled by a control signal detected by the control signal detection circuit and a timing signal output from the timing signal generation circuit. .