JPH07320395A - Sound signal reproducing device - Google Patents

Abstract

PURPOSE:To eliminate an abrupt change in sound volume and a feeling of physical disorder from sounds by connecting a voltage-controlled amplifier circuit which can change amplified gains against sound signals above a reference level reproduced from a linear track to the poststage of a DMSS circuit. CONSTITUTION:The characteristics of a VCA circuit 14 are set so that the amplified gain of the circuit 14 can become a fixed value, for example, 0dB against sound signals below a reference level of -8dB. In addition, the circuit 14 is constituted so that the amplified gain can change when the level of the sound signals S1' exceeds the reference level. For example, the gain is set at A1, A2,..., An dB. The gain of the circuit 14 is controlled based on the data of a DMSS circuit 6 or the sounds processed by the circuit 6. Therefore, the level difference against reproduced Hi-Fi sounds obtained during ordinary reproduction and a feeling of physical disorder against sounds which are reproduced in a special reproducing mode can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproduction output level of a linear track audio signal during special reproduction for an FM audio signal.

[0002]

2. Description of the Related Art Conventionally, it is well known that a memory circuit is used to reproduce an audio signal recorded on a linear track to obtain an audio output even in a special reproduction mode (double speed reproduction, five times speed reproduction, etc.). For example, Japanese Patent Laid-Open Publication No. Sho 5
See 9-45607 (G11B 5/027). FIG. 5 shows a general circuit block diagram thereof, and FIG. 6 shows recording tracks of the magnetic tape.

In FIGS. 5 and 6, 1 is an audio reproduction signal S1 recorded on the linear tracks 15a and 15b.
Input terminal, 2 is an equivalent amplifier circuit, 3 is an A / D conversion circuit that converts an analog signal into a digital signal, 4 is a memory circuit that stores a digital signal, and 5 is D / A conversion that converts a digital signal into an analog signal It is a circuit, and the A / D conversion circuit 3, the memory circuit 4, the D / A conversion circuit
A memory sound system (hereinafter referred to as DMSS) circuit 6 is configured. However, in FIG. 5, the DMSS circuit 6
A control circuit for controlling writing / reading to / from the memory circuit 4 is omitted. Reference numeral 7 is a changeover switch, and 8 is a buffer amplifier.

Reference numeral 9 is an input terminal for the FM audio reproduction signal S2 (HiFi audio signal) recorded on the diagonal track 16, 10 is a HiFi audio reproduction processing circuit, 11 is a changeover switch, 12 is an output terminal for the reproduced audio signal, and 13 is DMS
It is an output terminal for outputting a control signal S3 by pressing an S button (not shown). When this DMSS button is pressed, the changeover switches 7 and 11 are forcibly switched to the H side.

When the audio reproduction signal S1 is input to the terminal 1, it is amplified by the equivalent amplifier circuit 2 and the changeover switch 7
An audio signal is output to the output terminal 12 through the L terminal, the buffer amplifier 8, and the H terminal of the changeover switch 11.
Further, when the HiFi voice signal S2 is input to the terminal 9, the signal S2 is processed by the HiFi voice reproduction processing circuit 10 and then the terminal 12 via the L terminal of the changeover switch 11.
A HiFi voice signal is output to.

When the DMSS button is pressed, the control signal S3 is output and the changeover switches 7 and 11 are changed over to the H side. The audio reproduction signal S1 input to the input terminal 1 is amplified by the equivalent amplification circuit 2, then input to the DMSS circuit 6, converted from analog to digital by the A / D conversion circuit 3, and then at a predetermined timing. It is written in the memory circuit 4, read at a predetermined timing, converted again from digital to analog in the D / A conversion circuit 5, and passed through the H terminal of the changeover switch 7, the buffer amplifier 8, and the H terminal of the changeover switch 11. The processed reproduced audio signal is output to the terminal 12.

Here, the DMSS circuit 6 reproduces the signal recorded on the linear track even in the special reproduction mode of the magnetic tape, for example, the double speed reproduction or the quintuple speed reproduction, and the double speed reproduction is performed. , The read signal S1 is written / read to / from the memory circuit 4 by half the amount of information as in normal reproduction. Also, at the time of 5 × speed reproduction, by writing / reading the information amount of 1/5 of that at the time of normal reproduction to / from the memory circuit 4, a reproduced audio signal that can be heard even in the special reproduction mode can be obtained.

[0008]

By the way, the reproduced audio signal S1 'which has been signal-processed through the DMSS circuit 6 is used.
Is output at a fixed level, the following problems occur. That is, the reproduced audio signal processed by the DMSS circuit uses the signal recorded on the linear track. The recording level of the audio signal recorded on the linear track is set to a reference level (here, by an automatic level control (ALC) circuit during recording).
-8 dBs. ) The above signals are recorded with suppressed levels.

On the other hand, the HiFi audio signal recorded on the diagonal track of the magnetic tape can be recorded up to a signal level of about +20 dB with respect to the reference level. Therefore, when the DMSS circuit processes the audio signal of the reference level or higher, a considerable level difference occurs as compared with the HiFi audio signal. Conversely, if the level of the reproduced audio signal processed by the DMSS circuit is set to a level higher than the reference level and matched with the level of the HiFi audio reproduced signal during normal reproduction, the level of the reproduced audio signal becomes large overall. Become.

[0010]

A digital memory sound system (DMSS) circuit including an A / D conversion circuit, a memory circuit and a D / A conversion circuit is provided, and a linear track reproduction audio signal or a diagonal track reproduction HiFi audio is provided. A magnetic reproducing device which selectively outputs any of the signals and outputs the linear track reproduction audio signal through the DMSS circuit during special reproduction, wherein the linear track reproduction audio signal is provided at a stage subsequent to the DMSS circuit. A voltage controlled amplification (VCA) circuit for varying the amplification gain for a signal whose level exceeds the reference level is subordinately connected.

The amplification gain of the VCA circuit is 0 dB when the level of the reproduced audio signal is below the reference level, and variably increases when it exceeds the reference level. Also, the reference level is set to -8 dBs.

[0012]

With the above arrangement, the audio reproduction signal recorded on the linear track is D
After the signal processing is performed by the MSS circuit, a signal having a reference level or higher is variably amplified by the VCO circuit according to the reproduction signal level, and the level difference from the HiFi audio reproduction signal during normal reproduction is eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to the drawings. 1 is a circuit block diagram of the present invention, FIG. 2 is an input / output level diagram of a HiFi audio reproduction signal, FIG. 3 is an input / output diagram of a linear track audio reproduction signal, and FIG. 4 is an input of an audio reproduction signal after DMSS processing of the present invention. FIG. In the figure, the same parts as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted. In FIG. 1, the only difference from the conventional example is that a voltage-controlled amplification (VCA) circuit 14 is connected downstream of the DMSS circuit 6.

In the present invention, the linear track reproduction audio signal in the special reproduction mode is processed through the DMSS circuit 6, and the level difference between the level of the processed signal and the reproduction HiFi audio signal in the normal reproduction is VCA. (Voltage Co
This is improved by the ntrolled amplifier) circuit 14.

FIG. 2 shows the input-to-output level of the HiFi audio signal during normal reproduction, and recording / reproduction is possible up to a level exceeding about 20 dB. On the other hand, FIG. 3 shows the input versus output of the audio signal recorded on the linear track. Comparing FIG. 2 and FIG. 3, when the input signal exceeds the reference level (set to −8 dBs), the output level is saturated as shown in FIG. This is because the audio signal recorded on the linear track is controlled by the above-mentioned ALC circuit in order to suppress the distortion rate to, for example, 3% or less in order to secure the distortion rate due to the electromagnetic conversion characteristics depending on the relationship between the tape running speed and the magnetic head. It is recorded below the standard level.

In order to improve this level difference, for the audio signal S1 'whose characteristic is less than the reference level, the VCA circuit 14 has a gain of 0 dB so that the amplification gain becomes constant.
To be set. When the level of the reproduced audio signal S1 'exceeds the reference level -8 dB, the VCA circuit 1
It is designed to have a circuit configuration in which the amplification gain of 4 is varied (in this case, the gain is increased). For example, the gain is A1, A2, ... AndB as shown in FIG. still,
The gain control of the VCA circuit 14 is determined based on the data of the DMSS circuit 6 or the audio signal after the DMSS circuit 6 processing.

With the above-described structure, the audio signal reproduced from the linear track, which has been generated in the special reproduction mode, is processed by the DMSS circuit 6 and then
By being amplified by the VCA circuit 14, the level difference from the reproduced HiFi sound obtained during normal reproduction is eliminated, and the sense of discomfort with respect to the reproduced sound in the special reproduction mode can be eliminated.

[0018]

According to the above-described structure, HiFi during normal reproduction is provided.
Even if you are listening to the sound, switch to the special playback mode such as cue or review, and listen to the playback audio from the linear track by operating the DMSS button, if the playback audio level is below the reference level, there is no problem. Also, since the reproduced sound above the reference level is amplified with a variable gain according to the level, a sudden change in the volume of the TV or the like,
It is possible to eliminate the discomfort of voice.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of the present invention.

FIG. 2 is an input / output level diagram of a HiFi audio reproduction signal.

FIG. 3 is an input / output diagram of a linear track audio reproduction signal.

FIG. 4 is an input / output diagram of an audio reproduction signal after DMSS processing of the present invention.

FIG. 5 is a circuit block diagram of a conventional example.

FIG. 6 is a diagram showing audio signal recording tracks on a magnetic tape.

[Explanation of symbols]

3 A / D conversion circuit 4 Memory circuit 5 D / A conversion circuit 6 Digital memory sound system (DMS
S) circuit 14 voltage controlled amplification (VCA) circuit

Claims (5)

[Claims] 1. An A / D conversion circuit, a memory circuit, and a D / A.
A digital memory sound system (DMSS) circuit including a conversion circuit is provided to selectively output the first audio signal or the second audio signal, and at the time of special reproduction, the DMS.
A magnetic reproduction apparatus for outputting the first audio signal via an S circuit, the voltage-controlled amplification for varying the amplification factor for a signal in which the level of the first audio signal exceeds a reference level, in a stage subsequent to the DMSS circuit. An audio signal reproducing device having a (VCA) circuit connected thereto. 2. The amplification gain of the VCA circuit is 0 dB when the level of the reproduced audio signal is below a reference level.
The audio signal reproducing apparatus according to claim 1, wherein the audio signal reproducing apparatus variably increases when the reference level is exceeded. 3. The audio signal reproducing apparatus according to claim 1, wherein the first audio signal is an audio signal recorded on a linear track on a magnetic tape. 4. The audio signal reproducing apparatus according to claim 1, wherein the second audio signal is a frequency-modulated (FM) audio signal recorded on an oblique track on a magnetic tape. 5. The audio signal reproducing device according to claim 1, wherein the reference level is set to −8 dBs.