JPH0638162A - Recording and reproducing device for plural-signal systems - Google Patents

Abstract

PURPOSE:To select signals of different systems smoothly by providing a discrimination circuit discriminating and latching each signal system of plural signal inputs so as to avoid discrimination dissidence in the signal system changeover for plural inputs. CONSTITUTION:The result of signal discrimination of each input signal of a recording and reproducing device 5 is stored by a discrimination circuit 2 and a video audio circuit 3 is controlled so as to discriminate the signal discrimination system after input switching forcibly at the changeover of input. Thus, the changeover of the output of the recording and reproducing device and the changeover of signal system discrimination are implemented simultaneously and since an audio carrier frequency of an RF output of the recording and reproducing device (audio carrier inputted to a TV) and an audio carrier frequency of the audio carrier of the TV are coincident, no defect is caused in the TV side audio output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-signal type recording / reproducing apparatus, and more particularly to signal type discrimination at the time of signal input switching.

[0002]

2. Description of the Related Art A conventional apparatus is disclosed in, for example, Japanese Patent Laid-Open No. 1-228.
As described in Japanese Patent No. 286, the signal system immediately before the reproduction state is maintained, and the discrimination is switched simultaneously with the stop only when the reproduction is switched to the stop.

[0003]

The above-mentioned prior art has considered the switching of signals of different systems at the time of reproduction and stop. However, no particular consideration was given to the switching of the signal system when a plurality of inputs were made, and there were the following problems.

In a multi-signal recording / reproducing apparatus, when input switching is performed between different signal systems, a certain time or more is required to determine the signal system after switching. This is such that the quality of the input signal to the recording / reproducing apparatus is not constant, but the judgment signal is output after judging the state for a certain fixed time. Naturally, during this period, the determination is made before input switching. On the other hand, since the discrimination on the TV side is immediately discriminated by the synchronizing signal of the input signal,
When the input on the recording / reproducing device side is switched, the discrimination is switched almost at the same time. However, the RF output of the recording / reproducing device side is the same as that before the input switching until the end of the determination, so that it becomes inconsistent with the audio carrier of the TV side for which the determination has been completed, and the TV side audio output. A big noise occurs,
There was a problem that caused a malfunction in use.

An object of the present invention is to eliminate the inconsistency between the audio carrier frequency RF output from the recording / reproducing apparatus and the audio carrier frequency receivable by the TV, which is shown in the above problems.
In other words, the purpose is to eliminate the discrepancy time of the signal system discrimination at the time of input switching.

[0006]

SUMMARY OF THE INVENTION In a multi-signal type recording / reproducing apparatus, the above-described object is to discriminate a system for each of a plurality of signals in advance at the time of input switching, and the signal system of the signal switched at the time of input switching. Immediately switch to.
This can be achieved by using a microprocessor for system control of the recording / reproducing apparatus.

[0007]

The input signal used by the above means is discriminated and stored by the microprocessor for system control of the recording / reproducing apparatus. Since the signal system stored in the microprocessor or the like is switched at the same time when the input / output of the recording / reproducing device is switched, the problem of discrepancy in discrimination does not occur. Even if the discrimination of each input signal of the recording / reproducing apparatus is different, the discrimination of one input signal hardly changes continuously, and even if the discrimination of one input signal changes, the input switching is not performed. Unless they change at the same time, there is no malfunction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the periphery of a discrimination circuit using a system control microprocessor in a recording / reproducing apparatus. 1a to 1z are input terminals, 2 is a discriminating circuit using a system control microprocessor (hereinafter abbreviated as discriminating circuit), 3 is a video / audio circuit, 4 is an RF output circuit, and 5 is a TV. Discrimination circuit 2 discriminates and holds each signal system for a plurality of signals input to video / audio circuit 3 from input terminals 1a to 1z, and at the same time as switching of inputs, system of video / audio circuit 3 and RF output circuit 4 Switch.

FIG. 2 is a timing chart of the signal system discrimination by the discrimination circuit 2 of FIG.

FIG. 2 (a) shows a conventional structure, and FIG. 2 (b) shows a structure after implementing the invention. Reference numeral 6 is an output from the recording / reproducing apparatus, and reference numeral 7 is a signal system discrimination which is discrimination P when "1" and discrimination N when "0". 8 is voice MUTE when it is "1", when MUTE is ON, when it is "0"
It is MUTE OFF. Reference numeral 9 denotes an input switching control signal, which is input switching at "1" and no input switching at "0". 10 is a sound carrier of RF output of the recording / reproducing apparatus, 12
Is an audio carrier to be input to the TV side, 13 is a TV carrier, and B is an N signal system carrier frequency of 4.5 MHz.
z and C are P signal system voice carrier frequencies of 5.5 MHz
Is. Reference numeral 11 is a TV side signal system discrimination. Point A is an input switching point. t1 and t3 are signal system discrimination switching points, and t1-t2 is a time difference between the output switching and the discrimination switching in the recording / reproducing apparatus. The TV sound carrier 13 is switched in association with the TV side signal system determination 11.

As shown in FIG. 2A, in the conventional system, the video / audio circuit 3 is controlled by the input switching control signal at the time of switching the input.
However, there is a time difference between t1 and t2 between the input switching point A (switching of the recording / reproducing apparatus output 6) and the switching of the signal system determination 7. The signal system discrimination 11 on the TV side is switched almost at the same time as the input switching point A (switching of the output 6 of the recording / reproducing apparatus), but the audio carrier 10 (T
There is a problem that a large noise occurs in the TV-side audio output because the audio carrier frequency mismatch between the audio carrier 12) input to the V side and the TV audio carrier 13 occurs between t1 and t2.

Next, the present invention will be described with reference to FIG. First, the signal discrimination result of each input signal of the recording / reproducing apparatus is stored in the discrimination circuit 2, and at the time of input switching, the video / audio circuit 3 is controlled so that the discrimination is switched to the signal discrimination system after the input switching. As a result, the switching between the recording / reproducing device output 6 and the signal system discrimination 7 is performed at the point A (t3) at the same time, and the RF carrier of the recording / reproducing device 10 (audio carrier 12 input to the TV side). ) And TV
Since the voice carrier frequency of the voice carrier 13 of
There will be no problem in the audio output on the TV side.

[0014]

According to the present invention, it is possible to eliminate the discrepancy in discrimination when the signal system is switched when a plurality of inputs are input, and to smoothly switch signals of different systems. Further, since it can be achieved by the correspondence of the microprocessor discrimination program, the economical effect is great.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a peripheral of a discrimination circuit using a system control microprocessor in a recording / reproducing apparatus.

FIG. 2 is a timing chart of a signal type determination circuit by the determination circuit 2 of FIG.

[Explanation of symbols]

1a to 1z ... Input terminals, 2 ... Discrimination circuit, 3 ... Video / audio circuit, 4 ... RF output circuit, 5 ... Recording / reproducing device output, 6 ... T
V, 7 ... When the signal method is "1" When the determination is P, "0"
Judgment N, 8 ... When the voice MUTE is "1" MUTE O
N, "0" MUTE OFF, 9 ... Input switching control signal is "1" Input switching, "0" No input switching 10 ... Audio carrier of RF output of recording / reproducing device, 11
... TV side signal system discrimination, 12 ... TV side input audio carrier, 13 ... TV audio carrier, A ... input switching point, B ... N signal type audio carrier frequency 4.5 MH
Audio carrier frequency of z, C ... P signal system 5.5 MH
z, t1, t3 ... Signal system discrimination switching point, t1-t2 ... Time difference between output switching and discrimination switching in the recording / reproducing apparatus.

Claims (1)

[Claims] 1. A multi-signal type recording / reproducing apparatus having a discriminating circuit for discriminating and holding each signal system of a plurality of signal inputs and discriminating and switching at the same time as switching of inputs.