JPH02116281A - Multiple sampling signal adapter device - Google Patents

Abstract

PURPOSE:To reduce the circuit scale of digital recording/reproducing equipment by treating a low-bit (eight-bit) signal in the digital recording/reproducing equipment. CONSTITUTION:When the video of an analog MUSE signal is reproduced, switches SW1 to SW5 are respectively connected to a terminal A side. Thus, a signal to have passed through a nonlinear level extending circuit 35, a de- emphasis circuit 36 and a transmission inverse gamma circuit 37, and affected by a transmission path compensation is inputted to a MUSE video signal processing part 35. On the other hand, the signal to have passed through the nonlinear level extending circuit 51, a de-emphasis circuit 52 and a transmission inverse gamma circuit 53 is derived to a digital output terminal 54 as the MUSE signal at eight bits. In addition, an internal clock obtained by a timing generator 42 is guided to the digital output terminal 54 as well. The digital MUSE signal derived here is supplied to the digital recording/-reproducing device, and recorded on a recording medium. Since the data at low bits are supplied to the digital recording/reproducing equipment such as a magnetic recording/ reproducing device, a load can be reduced.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) This invention relates to a multiplex subsampling transmission/reception system (for example, M
The present invention relates to a multiplex subsampling signal adapter device that is applied to a MUSE decoder (MUSE system) and is effective when coupling a MUSE decoder with a digital recording/reproducing device.

(Prior Art) The MUSE system has been developed as a high-definition television transmission system. This method is used, for example, in Japanese Patent Application No. 60-1061.
It is also described in literature such as No. 32, NHK Technical Research Vol. H, NO2. The MUSE method converts high-definition television signals into 8.1M multiplexed subsampling signals.
The band is compressed to Hz and transmitted using, for example, satellite broadcasting, and in order to reproduce it, it is received by a satellite broadcasting receiver, demodulated, and then reproduced using a so-called MUSE decoder.

FIG. 7 shows a satellite broadcast receiving system that receives television signals using the MUSE method.

Satellite broadcast waves received by an antenna 1 are received and demodulated by a satellite broadcast tuner (hereinafter referred to as BS tuner) 2 and supplied to a selector 3 . The selector 3 can guide the received signal to the MUSE decoder 4 as well as to a high-definition device (for example, a magnetic recording/reproducing device) 6.

The high-quality television signal reproduced by the MUSE decoder 4 is introduced to the monitor 5 and displayed.

For the magnetic recording/reproducing device 6, digital signal processing circuits have recently been developed along with the development of digital technology, and as an adapter between the magnetic recording/reproducing device and the MUSE system, a configuration as shown in FIG. 6 has been developed. Conceivable.

That is, the MUSE baseband signal demodulated by the BS tuner is input to the analog-to-digital converter 11 via the input terminal 10. This analog digital converter 1
The output of No. 1 is 10-bit data, which is connected to the digital output terminal 12 and one input section a of the mode changeover switch 13.
supplied to

The reason why the output of the analog-to-digital converter 11 is set to 10 bits is because approximately 10 bits of resolution is required when performing nonlinear level expansion, de-emphasis processing, etc. for transmission path compensation. The other input section of switch 13 is connected to digital input terminal 14 . The digital output terminal 12 and the digital input terminal 14 are respectively connected to an input terminal and an output terminal of a magnetic recording/reproducing device as a high-definition device. The output signal selected by the mode switch 13 is supplied to a nonlinear level expansion circuit 15, level expanded, and then supplied to a primary de-emphasis circuit 16. This is because level compression and pre-emphasis are performed on the transmitting side to reduce signal distortion in the transmission path.

Further, the output of the de-emphasis circuit 16 is input to a transmission inverse gamma circuit 17, outputted as 8-bit data, and supplied to a video signal processing section 18 as a decoder.

When reproducing the MUSE signal from the magnetic recording/reproducing device, the switch 13 is switched to the terminal side. Note that the output of the mode switch 13 is transmitted to the control signal reproducing section 19.
, the synchronization detection circuit 20, and the audio processing section 2.2. The synchronization signal detected by the synchronization detection circuit 20 is supplied to a timing generator 21 and used to obtain a system clock and various timing signals.

(Problems to be Solved by the Invention) The adapter shown in FIG. The configuration is such that 10-bit data is reproduced and input to the switch 13. With this type of adapter, since the data handled by the magnetic recording/reproducing device is 10 bits,
There is a problem that the circuit configuration of the digital recording/reproducing path becomes complicated. Furthermore, the memory used in the digital recording/reproducing circuit also requires a large capacity and is expensive.

Therefore, this invention uses 8 bits (25 bits) to obtain image reproduction.
Focusing on the fact that data with 6 gradations is sufficient, this multiple subsampling signal adapter supplies low-bit data to digital recording and reproducing devices such as magnetic recording and reproducing devices, reducing the burden on them. The purpose is to provide equipment.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes an analog-to-digital converter that converts a signal from an analog input terminal to which a multiplex subsampling signal received and demodulated by a tuner is supplied into a digital signal. , the first one to which the output of this analog-to-digital converter is supplied.
a human power section and a second section that is supplied with external digital inputs.
a first switch means having an input section for selecting and deriving one of the signals according to a mode switching signal; and a nonlinear level expansion circuit to which an output signal of the first switch means is supplied. A de-emphasis circuit to which the output of the non-linear level expansion circuit is supplied; a transmission path compensation means comprising a transmission inverse gamma circuit to which the output of the de-emphasis circuit is supplied; and a sampling signal decoder to which the output of the transmission inverse gamma circuit is supplied. , an 8-bit data output terminal to which the output of the inverse gamma circuit is supplied, and a state in which the first switch means selects the second input section, instead of the selected state of the output of the transmission inverse gamma circuit. Said first
and second switch means for selecting an output signal from the switch means and supplying the selected signal to the sampling signal decoder and the 8-bit data output terminal.

(Function) With the above means, the digital recording and reproducing device can handle low-bit (8-bit) signals, and the circuit scale of the digital recording and reproducing device can be small.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The input terminal 30 has an analog MUSE received and demodulated by the BS tuner.
A signal is provided. This analog MUSE signal is subjected to clamping processing by a clamp circuit 32 via a low-pass filter 31, and then input to an analog-to-digital converter 33. This analog-to-digital converter 33 performs quantization of 10 bits per sample, and its output is supplied to terminal A of mode switch SW1. This switch SWI selects either terminal A or terminal B and supplies its output to nonlinear level expansion circuits 35 and 51. A digital input terminal 55 is connected to terminal B of the switch SWI, and an output terminal of an external digital recording/reproducing device is connected here.

The output of the nonlinear level expansion circuit 35 can be input to the de-emphasis circuit 36 via the switch SW2,
The output of this de-emphasis circuit 36 is the switch SW3.
It can be input to the transmission inverse gamma circuit 37 via. The output of this transmission inverse gamma circuit 37 is the switch S.
It can be input to the MUSE video signal processing unit 38 via W4.

FIG. 2 shows an example of nonlinear level expansion characteristics, and FIG. 3 shows an example of de-emphasis characteristics. Further, FIG. 4 is an example of transmission inverse gamma characteristics for a luminance signal.

Since the transmission inverse gamma characteristic for the color signal is different from that for the luminance signal, gamma correction suitable for the luminance signal and the chrominance signal is performed at different timings.

Here, switch SW2. SW3. When all of the SW4 select the input terminal B side, the output of the switch SWI can be directly input to the MUSE video signal processing section 38. Also, switch SW2. SW3. When the SW4 selects the input terminal A side, a series circuit of a nonlinear level expansion circuit 35, a de-emphasis circuit 36, a transmission inverse gamma circuit 37, and a MUSE video signal processing section 38 is formed.

The circuit configuration including the nonlinear level expansion circuit 51, the switch 5W12, the de-emphasis circuit 52, the switch 5W13, the transmission inverse gamma circuit 53, and the switch 5W14 is also similar to the configuration from the nonlinear level expansion circuit 35 to the switch SW4. However, the output of switch 5W14 is
It is connected to a digital output terminal 54.

The output of the switch SW1 is also supplied to timing signal generating means for obtaining system synchronization and control signal reproducing means for controlling the system. The control signal reproducing section 39 reproduces various control signals included in the MUSE signal. As a control signal, for example, when image motion information is used to perform reso-coding, it is used as control information for correcting the field position and adjusting it to the next field. On the other hand, the timing signal generating means is used to supply the synchronization signal detected by the synchronization detection circuit 41 to the timing generator 42 to obtain various timing signals. Also, the phase comparator 43, switch SW
5. The loop formed by the voltage controlled oscillator 45 and the timing generator 42 forms a phase locked loop, and synchronizes the phase of the internal clock with the sampling clock of the received signal. Here, when the switch SW5 selects the output of the phase comparator 44 and supplies it to the voltage-controlled oscillator 45, a phase-locked loop is formed by the voltage-controlled oscillator 45, the timing generator 42, and the phase comparator 44, and the internal clock is synchronized in phase with the external data sampling clock supplied from the digital input terminal 55.

One embodiment of the present invention is configured as described above.

When reproducing the video of the analog MUSE signal, the switches SWI to SW5 are connected to the respective terminal A sides. As a result, the MUSE video signal processing section 38 includes a nonlinear level expansion circuit 35. de-emphasis circuit 36,
A signal that has undergone transmission path compensation is input through the transmission inverse gamma circuit 37.

On the other hand, the signal passing through the nonlinear level expansion circuit 51, the de-emphasis circuit 52, and the transmission inverse gamma circuit 53 is outputted to the digital output terminal 54 as an 8-bit MUSE signal. The internal clock obtained by the timing generator 42 is also led to this digital output terminal 54. The digital MUSE signal derived here is supplied to a digital recording/reproducing device and recorded on a recording medium (disk, magnetic tape, etc.).

On the other hand, when reproducing a digital MUSE signal from a digital recording/reproducing device, an 8-bit digital signal and a reproduction II book are supplied to the digital input terminal 55. At this time, the switches SW1 to SW5 are respectively switched and connected to the terminal B side.

Therefore, the internal clock in the adapter is phase-synchronized with the reproduced clock from the digital recording/reproducing device, and
The digital MUSE signal introduced into switch SW1 is
The signal is input to the MUSE signal processing section 38 via switches SW2, SW3, and SW4. As a result, the MUSE signal from the digital recording/reproducing device is reproduced. On the other hand, the digital MUSE signal led out to the digital output terminal through the path of the switch 5W12.5W13.5W14 is used, for example, for dubbing.

FIG. 5 shows another embodiment of the invention. The previous example is
The transmission path compensator and switch row were configured in two sets,
In the embodiment shown in FIG. 5, the positions at which the digital output terminals 54 are taken out are devised to form one set. That is, in this embodiment, the digital output terminal 54 is connected to the MUSE video signal processing section 38.
is connected to the input section of the And the nonlinear level expansion circuit 51 and the de-emphasis circuit 52 in the previous embodiment.
, transmission inverse gamma circuit 53, switch 5W12.5W13
．． 5W14 is omitted. Even with this configuration, the same effect as the previous embodiment is obtained. In addition, digital input terminal 5
The 8-bit data introduced from 5 and the 8-bit data output from the transmission inverse gamma circuit 37 are adjusted to have the same weighting.

[Effects of the Invention] According to the above-mentioned invention, it is noted that 8-bit (256 gradation) data is sufficient for image reproduction, and it is possible to use low data for digital recording and reproducing equipment such as magnetic recording and reproducing devices. It is possible to reduce the burden by supplying bit data. Furthermore, the recording efficiency for digital recording media is also improved compared to 10-bit recording.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of nonlinear level expansion characteristics, FIG. 3 is a diagram showing an example of de-emphasis characteristics, and FIG. 4 is a diagram showing an example of transmission inverse gamma characteristics. FIG. 5 is a block diagram showing another embodiment of the present invention, FIG. 6 is a diagram showing a conventional example of an adapter device, and FIG. 7 is an explanatory diagram showing a satellite broadcast receiving system. 31...Low pass filter, 32...Clamp circuit, 3
3...Analog-digital converter, 35.51...Nonlinear level expansion circuit, 36.52...De-emphasis circuit, 37.53...Transmission inverse gamma circuit, 38...
・MUSE video signal processing section, SW1 to SW3゜5W12
~5W14...Switch, 54...Digital output terminal, 55...Digital input terminal.

Claims (2)

[Claims] (1) an analog-to-digital converter for converting a signal from an analog input terminal into a digital signal, to which the multiple subsampled signal received and demodulated by the tuner is supplied; and a first analog-to-digital converter to which the output of the analog-to-digital converter is supplied. a first switch means having an input section and a second input section to which a digital input from the outside is supplied, and selecting and deriving one of the signals according to the mode switching signal; Transmission path compensation means comprising a nonlinear level expansion circuit to which the output signal of the switch means is supplied, a de-emphasis circuit to which the output of the non-linear level expansion circuit is supplied, and a transmission inverse gamma circuit to which the output of the de-emphasis circuit is supplied; a multiple subsampling signal decoder to which the output of the transmission inverse gamma circuit is supplied; an 8-bit data output terminal to which the output of the inverse gamma circuit is supplied; the first switch means selecting the second input section; In this state, a second switch selects the output signal from the first switch means instead of the selection state of the output of the transmission inverse gamma circuit and supplies it to the multiplex subsampling signal decoder and the 8-bit data output terminal. 1. A multiplex subsampling signal adapter device, comprising: switch means. (2) Two sets of the transmission path compensation circuit and the second switch means are provided, the output of one set is supplied to the sampling signal decoder, and the output of the other set is supplied to the 8-bit data output terminal. 2. The multiple subsampling signal adapter device according to claim 1, wherein the multiple subsampling signal adapter device is configured to