JPS6051163B2 - Digital signal recording and reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital signal recording and reproducing apparatus, and particularly when used for recording and reproducing audio signals, an object of the present invention is to improve the SN ratio and distortion rate of analog signals during editing.

2. Description of the Related Art Recording and reproducing methods using digital signals have recently been increasingly applied to the field of audio signals.

When recording and reproducing audio signals by pulse code modulation, there is a disadvantage that editing cannot be performed accurately compared to the analog method. In order to eliminate this drawback, an analog circuit system for recording and reproducing the audio signal in analog form is provided separately, and an analog track is provided on the recording medium, such as a magnetic tape, in addition to one for pulse code modulation, so that the It uses a method that uses analog signals recorded on analog tracks. When recording analog signals such as audio signals on magnetic tape, there are three possible methods: non-bias, direct current bias, and alternating current bias. Of these, the alternating current bias method has extremely superior distortion and signal-to-noise ratio. As is well known, it has been adopted. The high frequency signal frequency for AC bias is set to approximately three times or more the highest frequency of the analog signal to be recorded and reproduced, and an independent oscillator is installed as this high frequency signal generator. , it is customary that a part of the erase signal oscillator for the erase head is also used. On the other hand, when considering the MFM recording method, for example, the digital signal frequency of a multi-fixed head type that pulse-code modulates an analog input signal falls within the frequency range of the modulated wave signal for AC bias of the analog signal due to various signal processing conditions. In many cases, this digital signal is directly applied to the AC bias frequency signal of the analog signal, so a signal multiplexing method can be considered. What is more important is that the multiplexing method can reduce crosstalk, which causes disturbance noise, to the digital signal track adjacent to the analog signal track. Next, this effect will be explained. In general, in a multi-fixed head system, mutual crosstalk between adjacent digital signal tracks usually exists as a disturbance, although there are some differences depending on measures taken to prevent it. In particular, when the track spacing of multi-heads becomes narrower as part of efforts to increase the density of signal recording, the effect of this will become even more pronounced, and it is thought that this will become a factor in the performance differentiation of digital signal recording and reproducing devices. Removal has become a problem. The object of the present invention is to eliminate the above-mentioned drawbacks.

In this way, crosstalk from adjacent signal tracks normally corresponds to disturbance noise, but if the signal due to crosstalk has exactly the same frequency or phase as the signal to be recorded and reproduced, it is considered disturbance noise. It is clear that this does not work as a function, and the idea of the present invention lies in this point. That is, even when analog signal tracks are co-located with digital signal tracks as described above, the above effect can be obtained by using the digital signal of the adjacent track as the high frequency signal for AC bias of the analog signal and multiplexing this signal with the analog signal. It can be easily done.

Next, the present invention will be specifically explained with reference to FIGS. 1 and 2.
FIG. 1 is an electrical connection diagram in recording mode, where 1 is an analog signal input terminal and 2 is an analog signal amplifier.

3 is an adder that multiplexes the analog signal and the AC bias digital signal.

, 4 is an A/D signal processing circuit for pulse code modulating the analog signal from 1 to supply a digital signal to each head element of the multi-channel head 5. A part of the output of 4 is supplied to 3, the rest is supplied to head elements 5b to 5n of 5, and the output of 6b to 6n is supplied to D! Form a digital signal track.

Further, the output from 3 is supplied to the head element 5a of 5, and the output from 6 is supplied to the head element 5a of 5.
form an analog signal track of a. Note that the magnetic tape 7 is running in the direction of the arrow. FIG. 2 is a three-dimensional electrical connection diagram in the playback mode according to the present invention. Out of each signal track 6a to 6n on the magnetic tape 7, 5a reads out the analog signal of 6a, is played back by the playback amplifier 8, and is sent to the output terminal 9. applied.

5b to 5n are D/A's that read out the digital signal numbers of 6b to 6n and convert the digital signals to analog signals, respectively.
It is supplied to a signal processing circuit 10, and its output is outputted to an output terminal 11.
is applied to

In this multi-track fixed head type digital signal recording and reproducing device that records analog signal tracks and digital signal tracks side by side, the digital signal adjacent to the analog signal track is used as a high frequency signal for alternating current bias of the analog signal. By using this, it is possible to easily improve the SN ratio and distortion factor of analog signals, and at the same time, it is possible to obtain the effect of reducing crosstalk of digital signals.

As described above, the present invention can fully demonstrate the performance of a digital signal recording/reproducing apparatus by using very simple means, and can achieve its objectives simply and inexpensively.

[Brief explanation of the drawing]

FIG. 1 is an electrical connection diagram in a recording mode for explaining an embodiment of the present invention, and FIG. 2 is an electrical connection diagram in a reproduction mode similar to FIG. 1. In the figure, 1 is an input terminal, 2 is an analog signal amplifier, 3 is an adder, 4 is an A/D signal processing circuit, 5 is a multi-channel head, 6 is a signal track, 7 is a magnetic tape, 8 is a reproduction amplifier, 9 , 10 are output terminals, and 10 is a D/A signal processing circuit.

Claims (1)

[Claims] 1. In a digital signal recording/reproducing device comprising means for recording or reproducing an analog signal on a recording medium in a pulse code modulated format, and means for recording the analog signal in an analog state on the recording medium, the analog signal is A digital signal recording/reproducing device using the pulse code modulated signal as an alternating current bias signal.