JPH0254973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a BS tuner for receiving SHF broadcasting that is capable of recording and reproducing PCM signals as they are.

(Prior art) A conventional BS tuner inputs a first intermediate frequency signal to an IF conversion section, outputs this signal as a video signal through an FM detection section and a video signal processing section, and also outputs the signal as a video signal through a 4-phase DPSK demodulation section and a PCM It is designed to be output as an audio signal through a demodulator.

(Problem to be Solved by the Invention) However, in the conventional BS tuner described above, out of the four channels of audio (2 channels of TV audio, 2 channels of independent audio) sent in mode A of SHF broadcasting, 2 channels of audio are I can only choose. Furthermore, if the audio output of a BS tuner is recorded using an analog amplifier and a deck, the SN ratio of the audio signal will be limited by the performance of those devices.
Furthermore, in order to process a PCM signal, it is necessary to add a redundant code to the PCM signal and record it, and use that redundant code during playback to perform error detection, error correction, etc. Recording and reproduction required a complicated circuit configuration, which caused various problems such as increased costs.

The present invention was made in view of the above circumstances, and its purpose is to utilize the redundant code included in the PCM signal of SHF broadcasting, and to utilize the circuits already built into the tuner for error detection, error correction, etc. An object of the present invention is to provide a BS tuner for receiving SHF broadcasting, which is configured to appropriately record and reproduce audio included in a PCM signal of SHF broadcasting with an extremely simple circuit configuration.

(Means for Solving the Problems) In order to solve the above problems, the BS tuner for SHF broadcast reception of the present invention includes a digital demodulation section that demodulates PCM signals, and a PCM signal demodulated by the digital demodulation section.
a PCM demodulator that demodulates the PCM signal into an audio signal;
A switching unit is inserted between the digital demodulation unit and the PCM demodulation unit, and outputs a recording control signal or a reproduction control signal to the switching unit, and outputs a recording control signal or a reproduction control signal to the switching unit, and outputs a recording control signal or a reproduction control signal from the digital demodulation unit through the switching unit. input
a PCM signal recording and reproducing section for recording and reproducing PCM signals; when viewing SHF broadcasting, the digital demodulating section and the PCM demodulating section are connected via the switching section; inputting the PCM signal from the digital demodulation unit to the PCM demodulation unit;
When viewing SHF broadcasting and recording a PCM signal, the PCM signal from the digital demodulation section is outputted from the PCM signal recording/reproducing section to the switching section.
When the PCM signal is input to the PCM demodulation section and inputted to the PCM signal recording and reproducing section to reproduce the PCM signal, the PCM signal recording and reproducing section outputs the recording and reproducing signal to the switching section. In addition to blocking the PCM signal from the digital demodulation section, the reproduction PCM signal from the PCM signal recording and reproduction section
The signal is configured to be input to the PCM demodulation section via the switching section.

(Function) When viewing SHF broadcasting, the digital demodulation section and the PCM demodulation section are connected via the switching section.
This allows the PCM signal from the digital demodulator to
The signal is input to the PCM demodulator, demodulated into an audio output signal according to the audio mode set here, and output from the audio output terminal. In addition, when viewing SHF broadcasting and recording PCM signals, the PCM signal recording and reproducing section outputs a recording control signal to the switching section, thereby controlling the PCM signal from the digital demodulation section.
The signal is input to the PCM demodulation section via the switching section, and is also input to the PCM signal recording/reproducing section via the switching section. This allows the output from the digital demodulator to
The PCM signal is input to the PCM demodulation section, demodulated to an audio output signal according to the audio mode set here, and output from the audio output terminal, and the PCM signal from the digital demodulation section is input to the PCM signal recording and playback section. and record without degrading the SN ratio. Furthermore, when reproducing the PCM signal recorded in the PCM signal recording and reproducing section, the PCM signal from the digital demodulating section is cut off by outputting a recording and reproducing signal from the PCM signal recording and reproducing section to the switching section. At the same time, the reproduced PCM signal from the PCM signal recording and reproducing section is input to the PCM demodulating section via the switching section. As a result, in the PCM demodulation section,
Demodulates the audio output signal according to the set audio mode and outputs it from the audio output terminal.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

The drawing is a block diagram showing a BS tuner 1 for receiving SHF broadcasts according to the present invention.
BS tuner 1 receives the output of a BS converter (not shown) input from terminal 2 (first intermediate frequency signal S1).
In response to this, a video signal is output from the video output terminal 3, and an audio signal is output from the audio reproduction terminal 4. Further, the bit stream terminal 5 is adapted to take out an error-corrected PCM signal so that it can receive facsimile broadcasting or the like based on independent data contained in the PCM signal.

The first intermediate frequency signal S1 input to the terminal 2 is
An intermediate frequency conversion unit (IF conversion unit) together with the channel selection signal S2 output from the channel setting unit 6
7, the first intermediate frequency signal S1 is converted into a second intermediate frequency signal S3 having the selected signal component.

The second intermediate frequency signal S3 is input to the FM detection section 8, where it is FM detected and converted into a detected signal S4 consisting of a video signal component and a frequency division multiplexed signal component of an audio subcarrier. This detected signal S4 is input to a low-pass filter section 9 having a band of 4.5 MHz or less and a band-pass filter section 10 whose center frequency is 5.7 MHz, and the video signal S5 is separated in the low-pass filter section 9, and
The audio subcarrier S6 is separated in the bandpass filter section 10.

The separated video signal S5 is sent to the video signal processing section 1
1, the shaping processing such as pre-emphasis and energy diffusion signal superimposition performed to improve the signal-to-noise ratio during transmission is restored, and the signal is output from the video output terminal 3 as a regular composite video signal S11. It is becoming more and more common.

On the other hand, the separated audio subcarrier S6 has four phases.
The signal is input to the DPSK demodulator 12, where the phases of adjacent carrier waves are compared and demodulated into a PCM signal S7. This PCM signal S7 is input to the PCM demodulating section 14 via the switch section (switching section) 13, and is also input to the PCM signal recording/reproducing section 15.

The PCM demodulator 14 receives the input PCM signal S7.
From there, the audio output signal S8 is demodulated according to the audio mode set by the audio mode setting section 16, and is output to the audio output terminal 4. Furthermore, the PCM demodulator 14 performs processing such as deinterleaving and descrambling error correction on the PCM signal S7, and outputs it to the bit stream terminal 5.

On the other hand, by operating the recording circuit (not shown) of the PCM recording and reproducing section 16 and inputting the recording control signal S9 to the switch section 13, the PCM signal S7 output from the 4-phase DPSK demodulating section 12 is PCM demodulated. The signal is input to the PCM signal recording/reproducing section 15 as well as to the PCM signal recording/reproducing section 15 . Then, the PCM signal recording/reproducing section 15 records the PCM signal S7.

In addition, the reproduction circuit (not shown) of the PCM signal recording and reproduction section 15 is operated to generate the reproduction control signal S10.
By inputting the
PCM signal S7 output from the DPSK demodulator 12
The reproduced PCM signal output from the PCM signal recording and reproducing section 15 is input to the PCM demodulating section 14 via the switch section 13. Here, the reproduced PCM signal is demodulated into an audio signal and outputted from the audio output terminal 4.

That is, the BS tuner for SHF broadcast reception of the present invention has a switch section 13 and a conventional BS tuner.
It has a configuration in which a PCM signal recording/reproducing section 15 is added.

Next, we will explain the operation of the BS tuner for receiving SHF broadcasts, which has the above configuration, when you want to watch only SHF broadcasts, when you want to watch SHF broadcasts and also watch independent audio broadcasts later, and when you are watching SHF broadcasts and cannot hear them. If you want to listen to the independent audio later, it will be explained separately below.

If you want to watch only SHF broadcasts.

In this case, the four-phase
The DPSK demodulator 12 and the PCM demodulator 14 are connected (the above is the first mode). This results in 4
The PCM signal S7 from the phase DPSK demodulator 12 is
The PCM demodulator 14 demodulates the signal into an audio output signal S8 according to the audio mode set by the audio mode setting unit 16, and outputs it from the audio output terminal 4. In addition, the PCM demodulation unit 14 performs processing such as deinterleaving and descrambling error correction on the PCM signal S7.
PCM ready for immediate use as data
The signal is output to the bitstream terminal 5.

If you want to watch SHF broadcasts and also watch independent audio broadcasts later.

In this case, the PCM signal recording/reproducing section 15 outputs a recording control signal S9 to the switch section 13. As a result, in addition to operating in the first mode, the 4-phase DPSK demodulator 12
The PCM signal S7 is sent via the switch section 13.
The PCM signal S7 is input to the recording circuit of the PCM signal recording/reproducing section 15 and recorded (the above is the second
mode). At this time, the audio of the SHF broadcast itself also
Recording can be performed in the PCM signal recording/reproducing section 15 without deteriorating the SN ratio.

If you want to listen to independent audio that you were unable to hear while watching SHF broadcasts later.

In this case, a reproduction control signal S10 is sent from the PCM signal recording/reproducing section 15 to the switch section 13.
Output. As a result, the switch section 13
Cut the PCM signal S7 from SHF broadcast,
The reproduced PCM signal from the PCM signal recording/reproducing section 15 is input to the PCM demodulating section 14 . PCM demodulator 1
The reproduced PCM signal input to the audio output terminal 4 is demodulated into an audio output signal S8, and is output from the audio output terminal 4. In addition, the PCM demodulation section 14
Now, by applying processing such as deinterleaving and descrambling error correction to the reproduced PCM signal, it can be used immediately as data.
Output the PCM signal to the bitstream terminal 5.

In this way, the SHF broadcast receiving BS tuner of the present invention has the switch section 13 added to the conventional BS tuner.
By adding the PCM signal recording and reproducing section 15, it is possible to record the PCM signal while watching SHF TV broadcasting, and by playing back the independent audio later, there is no chance of missing the independent audio. It is. It also enables recording with less deterioration in the SN ratio, which is a feature of PCM broadcasting. Furthermore, the PCM
By simultaneously recording independent data included in the signal, it becomes possible to reproduce facsimile broadcasts, still image broadcasts, etc. Furthermore, conventional
When recording a PCM signal with a BS tuner, the PCM
A redundant code is added to the signal for recording, and a circuit must be added to perform error correction using the redundant code during playback. Utilizing the redundancy code included in the PCM signal,
Furthermore, error detection, error correction, etc. can be performed using circuits built into the tuner, resulting in an extremely rational configuration.

(Effect of the invention) The BS tuner for receiving SHF broadcasting of the present invention has
Since you can record PCM signals while watching TV broadcasts, you can freely play independent audio after watching TV broadcasts, and you can also use facsimile broadcasts,
Independent data such as still image broadcasts can also be reproduced. Also,
Since the PCM signal itself is recorded, recording with less deterioration of the SN ratio is possible. In addition, satellite broadcasting
Since error detection can be performed using the redundancy code included in the PCM signal, there is no need to add a new redundancy code, and processing such as error detection and error correction can be performed using the circuits originally built into the tuner. This can be done by using the switching part and
By adding a PCM signal recording and reproducing section, the SHF broadcast receiving BS of the present invention can be achieved by adding the minimum necessary circuitry.
It has the same effect that Chiyuna is able to achieve.

[Brief explanation of drawings]

The drawing is a block diagram showing the configuration of a BS tuner for receiving SHF broadcasting according to the present invention. 10...Band pass filter section, 12...4 phase
DPSK demodulation section, 13... switch section (switching section),
14...PCM demodulation section, 15...PCM signal recording/reproduction section.

Claims (1)

[Claims] 1. A digital demodulation section that demodulates a PCM signal; a PCM demodulation section that demodulates the PCM signal demodulated by the digital demodulation section into an audio signal; and between the digital demodulation section and the PCM demodulation section. a switching unit in which a recording control signal or a reproduction control signal is output to the switching unit, and recording and reproduction of a PCM signal input from the digital demodulation unit via the switching unit are performed. When viewing SHF broadcasting, by connecting the digital demodulation unit and the PCM demodulation unit via the switching unit, the PCM signal from the digital demodulation unit is connected to the PCM signal recording and reproducing unit. When inputting the PCM signal to the PCM demodulation section and viewing SHF broadcasting and recording the PCM signal, the PCM signal recording and reproducing section outputs a recording control signal to the switching section, so that the PCM signal from the digital demodulation section is input to the PCM demodulation section. PCM signal as above
When inputting the PCM signal to the PCM demodulation section and inputting it to the PCM signal recording and reproducing section, and reproducing the PCM signal, the PCM signal recording and reproducing section outputs the recording and reproducing signal to the switching section. A BS tuner for SHF broadcast reception, characterized in that a PCM signal from a digital demodulation section is blocked, and a reproduced PCM signal from the PCM signal recording/reproducing section is input to the PCM demodulation section via the switching section. .