JPS6288101A - Sound signal switching device for video tape recorder - Google Patents

Abstract

PURPOSE:To automatically select and reproduce a PCM signal and an FM signal by leading a reproducing PCM sound signal and a reproducing FM sound signal to an output terminal, in accordance with a signal outputted at the time when an error of a data transmission of the reproducing PCM sound signal does not exist, and when there is no signal, respectively. CONSTITUTION:A PCM signal from a head, which has been inputted to an input terminal 12 detects an error of a transmission data by a PCM data correcting circuit 7, and when a reproducing data is correct, a pulse of an error pointer output is outputted from the circuit 7. The pointer output is integrated 8 and sent to a switch control circuit 9, and an electronic changeover switch 10 is driven. As a result, PCM sound signals from input terminals 1, 2 are sent to output terminals 4, 5 through the switch 10 and an automatic/ manual changeover switch 11. When no pointer output exists in a prescribed period, an FM sound signal from an input terminal 3 is sent to the terminals 4, 5 through the switches 10, 11. In this way, the PCM signal and the FM signal are automatically selected and reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an audio signal switching device in a video tape recorder (VTR).

2. Description of the Related Art In recent years, recording of audio signals in VTRs (such as smi+ and jVTRs) has been accomplished using two methods: frequency modulating the audio signal, superimposing it on the video signal, and recording it along with the video signal using a rotating head, and recording the audio signal after PCM modulating the audio signal. A method of time-compressing the PCM audio signal and recording the time-compressed PCM audio signal using the rotary head prior to recording the video signal is also used. Therefore, during playback, this FM audio signal and PCM
It is necessary to select and reproduce the audio signal.

FIG. 2 shows a block diagram of the main parts of a conventional audio signal switching device for reproduction signals, where 1 and 2 are input terminals for the R channel and L channel of the reproduction PCM audio signal from the rotary head, respectively, and 3 is the input terminal for the R channel and L channel of the reproduction PCM audio signal from the rotary head. This is an input terminal for the reproduced FM audio signal. By switching the switch 6, either the PCM audio signal or the FM audio signal can be selected and output to the output terminals 4 and 6.

Problems to be Solved by the Invention However, in such a device, for example, if PCM audio and FM audio are recorded alternately on a videotape, the audio output must be alternated at each switching point during playback. It was necessary to switch manually. The present invention eliminates the above-mentioned drawbacks and is configured such that when a PCM audio signal is recorded, which has better sound quality than FM audio signal recording, the PCM audio signal is automatically played back. .

Means for Solving the Problems The present invention has an error correction unit (CRCC) for detecting and correcting data transmission errors in the PCM audio signal,
During playback, the data transmission error is detected using the signal from the error correction section, and if there is no error, a predetermined signal (error pointer output) indicating that there is no error is output. , the presence or absence of this error pointer output is detected, and if there is this error pointer output, the PCM audio signal is automatically selected.

Effect: With the above-described configuration, when a PCM audio signal is recorded, the selection is automatically switched to the PCM audio signal.

Embodiment Hereinafter, an audio switching device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an electrical block diagram during playback of the audio switching device according to an embodiment of the present invention, in which an error pointer output pulse is output from the input terminal, integrated by an integrating circuit 8,
It is sent to the switch control circuit 9, drives the electronic changeover switch 10, and switches its movable contacts f and i from contact e to cl.
, switch from h to q. PCM audio signals from input terminals 1 and 2 are sent to output terminals 4 and 5 via electronic changeover switch 1Q and automatic/manual changeover switch 11.

Next, if there is no error pointer output from the data correction circuit 7 for a certain period or more, the movable contacts f and i of the electronic changeover switch 10 are switched to contacts e and h, respectively. The FM audio signal from input terminal 3 is connected to electronic selector switch 1Q.
/ is sent to the output terminals 4 and 5 via the manual changeover switch 11.

That is, the movable contact piece 1 of the automatic/manual changeover switch 11
．． When o is connected to contacts j and m, if there is an error pointer output, the electronic changeover switch 10 operates and the PC
The M signal is output from the output terminals 4.5, and when there is no error pointer output, the FM signal is output from the output terminals 4 and 6. Note that the movable contact 1 of the automatic/manual changeover switch 11. .

When the contact point is connected to the n side, it is possible to manually switch between the PCM signal and the FM signal using the switch 6 as in the conventional example.

Effects of the Invention As described above, according to the present invention, when a PCM audio signal is recorded, it is possible to automatically select the PCM signal, so that the PCM signal and the FM audio signal are recorded alternately. Even if the PCM audio signal and FM audio signal are both recorded, the PCM audio signal that provides good sound quality is automatically selected. It is possible.

[Brief explanation of drawings]

FIG. 1 is an electrical block diagram of an audio signal switching device for a video tape recorder according to an embodiment of the present invention, and FIG. 2 is an electrical block diagram of an audio switching device in a conventional example. End: PCM data correction circuit, 8: Integrating circuit, 9°゛°°゛ switch control circuit, 10: Electronic changeover switch, 11: Automatic/manual switching switch.

Claims (1)

[Claims] Detects whether or not there is an error in data transmission of the reproduced PCM audio signal, and transmits the reproduced PC according to the signal output when there is no error.
An audio signal switching device for a video tape recorder configured to guide an M audio signal to an output terminal, and to guide a reproduced FM audio signal to an output terminal when the signal is not present.