JPH03280683A - Terminal equipment for catv - Google Patents

Abstract

PURPOSE:To obtain maximum separation at a television receiver coping with stereo sound without adjustment of sound volume by controlling sound volume so that a frequency shift of a main channel signal in a television signal is + or -25kHz at the detection of terminal equipment ON. CONSTITUTION:A CATV terminal equipment 11 is provided with a terminal equipment ON detection means 12 detecting it that a terminal equipment is turned on, and a sound volume control means 6' controls a sound volume control circuit 7 so that a frequency shift of an audio main channel signal in a television signal (f) is + or -25kHz at the detection of ON of the terminal equipment with the detection means 12. That is, when the terminal equipment is turned on, the ON-state is detected by the terminal equipment ON detection means 12 and the sound volume control means 6, controls the sound volume control circuit 7 so that a frequency shift of an audio main channel signal in a television signal (f) outputted from an RP output terminal 9 is + or -25kHz at the detection of ON of the terminal equipment with the detection means 12. Thus, maximum separation is obtained for the television receiver 10 coping with stereo sound.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a CATV endpiece device capable of receiving stereo broadcasts.

Conventional technology In recent years, the CATV industry has been using broadcasting satellites (B5) and communication satellites (C
S) TV signal retransmission is progressing towards multi-channeling, and the audio of the TV signal is U:X?
V-o broadcasts are becoming more common.

Hereinafter, a conventional CATV terminal device will be explained based on the drawings.

FIG. 3 is a block diagram of a portion related to television signals of a conventional CATV terminal device, to which a stereo compatible television receiver is connected. Parts related to data signals and parts related to control of each circuit are omitted.

In FIG. 3, an input signal C consisting of a television signal on which a stereo audio signal is superimposed, which is input from the CATV input terminal 2 of a CATV terminal unit l, is converted into an intermediate frequency signal by a tuner 3. , are input to the descrambler 4. The descrambling unit 4 restores the synchronously compressed signal to the original television signal C, and the television signal demodulation circuit 5 demodulates the signal into a video signal d and an audio stereo sound signal e. Normally, the television signal demodulation circuit 5 has a wideband design that sufficiently passes stereo sound frequencies.The audio signal C is converted in volume in a volume control circuit 7 controlled by a volume control means 6.
The signal is input to the RF modulator circuit 8. The video signal d and the audio signal C whose volume is controlled by the volume control circuit 7 are RF 7J! It is converted into a television signal f of a specific television channel by a circuit 8, and is supplied from an RF output terminal 9 to a stereo compatible television receiver IO.

In the above configuration, when the CATV input signal a is a television signal on which a stereo audio signal is superimposed, the separation of the stereo audio output from the stereo compatible receiver IO is controlled by the volume control circuit 7 controlled by the volume control means 6.
It will change depending on the volume. This is because although the volume of the main channel signal of the audio signal e is changed by the volume control circuit 7, the frequency shift does not change because the sub channel signal #iFM modulation is applied and superimposed on the main channel signal.

Problems to be Solved by the Invention In such a conventional CATV terminal device 1111, in order to obtain sufficient separation in the stereo TV receiver @ 1110, the volume control means 6 controls the volume of the volume control circuit 7 to a certain level. had to change. Theoretically, maximum separation can be obtained by controlling the volume control means 6 so that the frequency deviation of the main channel signal of the television signal f output from the RF output terminal 9 is ±25 KH2.

The present invention solves the above problem, and when the terminal device is turned on, the volume control means controls the frequency l! of the main channel signal! The object of the present invention is to provide a CATV terminal device with a deviation of ±25 KHz.

Means for Solving the Problems In order to solve the above problems, the present invention provides, in addition to the configuration of a conventional CATV terminal device, a detection means for detecting that the terminal device is turned on, and a terminal device using the detection means. The frequency deviation of the audio main channel signal of the television signal outputted from the RF modulator circuit at the time of ON detection is ±251.
G(z).

Furthermore, a second invention includes, in addition to the configuration of the first invention,
Setting whether or not the volume control means controls the volume control circuit so that the frequency deviation of the audio main channel signal of the television signal output from the RF modulator circuit is ±251G (z) when the detection means detects that the terminal device is turned on. It is provided with a setting means to do this.

Effect With the configuration of the first invention described above, when the terminal device is turned on, the volume control means adjusts the frequency deviation of the main channel signal by ±251.
By setting GizK, maximum separation can be obtained on a stereo compatible TV receiver without the need for the subscriber to change the frequency shift to +/-251 GI z.

Further, according to the configuration of the second invention, by setting whether or not to control the terminal device ON detection local wave number deviation to be ±25 KHz using the setting means, it is possible to eliminate the need to maximize separation without performing stereo reproduction. Compatible with monaural TV receivers without. In the Nananora M television receiver, there is no need to set the frequency deviation to ±251O (z).

EXAMPLE Hereinafter, one embodiment of the present invention will be explained based on the drawings. Note that the same components as those in FIG. 3 of the conventional example are given the same reference numerals and explanations are omitted.

111th! IFi is a block diagram of a part related to television signals of a CATV terminal device showing an embodiment of the present invention, and shows connection with a stereo compatible television receiver.

C of the present invention: ■Terminal device 11. , a terminal device on detection means 12 for detecting that the terminal device is turned on is added to the configuration of the conventional CATV terminal device 1, and a volume control means 6 is added.
1, when the detection means 12 detects that the terminal device is turned on,
The volume control circuit 10 is configured to control the frequency deviation of the audio main channel signal of the television broadcast Jijf to be ±25 KHz.

With the above configuration, when the terminal device is turned on, the terminal device on inspection means 12 detects that the terminal device is on, and in conjunction with the on detection means 12, the volume control means 6' outputs a television signal from the RF output terminal 9. The frequency deviation of fO main channel signal is ±
The volume control circuit 7 is controlled so that the signal becomes 251G (z). This provides the maximum separation in stereo TV reception!1110.

FIG. 2 shows a block diagram of a portion related to television signals of a CATV terminal device according to another embodiment of the present invention.

CATV terminal device 13Fi shown in Fig. 2, C in Fig. 1
A switch 14 connected to the volume control means 9 is added to the configuration of the ATV terminal device 11, and when the volume control means 61 is turned on by the switch 14 and the on-inspection means 12 detects that the terminal device is on, the TV signal f is The audio control circuit 10 adjusts the frequency deviation of the main channel signal to ±25KHzK.
The frequency shift is controlled such that the frequency shift is not controlled when the switch 14 is off or the detection means 12 is not detected.

According to the above configuration, when the terminal device is turned on, the terminal device on detection means 12 detects that the terminal device is on, and when the terminal device on detection means 12 is linked and the switch 14 is on, the volume control means 6a outputs the RF output. The volume control circuit 7 is controlled so that the frequency deviation of the main channel signal of the television signal f output from the terminal 9 is ±25 KHz.

As a result, maximum separation can be obtained in the stereo compatible television receiver IO. If switch 14 is off,
Volume side @ times # so that the frequency deviation is ±25KHz!
Does not control r7. The reason why the switch 14 is provided as a setting means for controlling whether or not to control the frequency deviation to be ±251a (z) when the terminal device is turned on is to be compatible with monaural television receivers. Since stereo reproduction is not possible with a monaural TV receiver, the frequency deviation of the audio must be ±25KHz to maximize separation.
, there is no need to do so.

In addition, as the setting means, C is controlled by a data signal.
In the case of ATV terminals it is also possible to use data signals.

Effects of the Invention As described above, according to the first invention, the frequency deviation of the main channel signal of the television signal is ±25 when the terminal device is turned on.
)G(z), so that there is no need to take the trouble of adjusting the volume using a remote controller or the like, and to provide a terminal device for CATV capable of obtaining the maximum separation in a stereo compatible television receiver. It is extremely valuable for eastern purposes.

Furthermore, according to the second invention, the setting means adjusts the frequency deviation to ±
By setting whether or not to set the frequency to 25 KHz, it is possible to support a monaural television receiver that does not perform stereo reproduction, that is, it is not necessary to set the frequency shift to ±25 KHz.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a CATV terminal device showing one embodiment of the present invention, and FIG. 2 is a block diagram of a CATV terminal device showing another embodiment of the present invention.
FIG. 3 is a block diagram of a conventional CATV terminal device. 3... Tuner, 4... Scramble canceling section, 5...
...TV signal demodulation circuit, 61.61... Volume control means, 7... Volume control circuit, 8... RF modulator, 10... Stereo compatible TV receiver, 11.13.
... CATV terminal device, 12... Terminal device on inspection means, 14... Switch (setting means), a... CA
TV input signal, b... intermediate frequency signal, C... television signal, d... video signal, e... audio signal,
f...TV signal.

Claims (1)

[Claims] 1. A demodulation circuit that converts a transmitted CATV input RF signal into an intermediate frequency to obtain a television signal and demodulates a video signal and an audio signal, and a demodulation circuit that demodulates a video signal and an audio signal; A CATV terminal device comprising an audio control circuit for controlling the video signal and an RF modulator circuit for converting the demodulated video signal and the audio-controlled audio signal back into a television signal, the terminal device being turned on. a detecting means for detecting that the terminal device is turned on; and controlling the volume control circuit so that the frequency deviation of the audio main channel signal of the television signal output from the RF modulator circuit is ±25 KHz when the detecting means detects that the terminal device is turned on. A CATV terminal device characterized by being provided with a volume control means. 2. Setting whether or not the volume control means controls the volume control circuit so that the frequency deviation of the audio main channel signal of the television signal output from the RF modulator circuit is ±25 KHz when the detection means detects that the terminal device is turned on. 2. The CATV terminal device according to claim 1, further comprising a setting means for configuring the CATV terminal device.