JPS58188312A - Muting circuit of tape recorder - Google Patents

Abstract

PURPOSE:To simplify the mechanism of the circuit and to obtain a tape recorder, by using the functions of the muting of recording and of reproduction in common with an AGC recording circuit. CONSTITUTION:A muting switch S3 is a reproducing muting switch at the reproduction, and when a voltage is applied to a transistor(TR) 2 via the switch S3 from a voltage applied terminal (d), the TR2 is set on, the input of an amplifier 1 is suppressed and operated as the muting of reproduction. On the other hand, at the recording, the switch S3 is a recording muting, the voltage is applied to the TR2 via the switch S3, and activated as the recording muting. Thus, the recording AGC is used in common for the recording muting and the reproduction muting, allowing to simplify the circuit constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape recorder, and the circuit is simplified by performing an AGC recording circuit, recording muting, and reproduction muting using the same transistor.

Figure 1 shows a conventional tape recorder, a
is the recording/playback magnetic head, b is the input terminal, C is the output terminal,
d is a voltage application terminal, and 81181 is a recording/playback changeover switch that is switched in conjunction with each other. S3 is a playback mute switch, S4 is a recording mute switch, 2, 5.6 are transistors, 3, 8, 9 are capacitors, 4 is a diode, 7°11 is a resistor, and l is a recording/playback amplifier. In the above configuration, when recording 8. , S2 are switched to the side shown in FIG. For this reason, a signal is applied to the head a via the input terminal switch S1, the switch F11, and the switch S2, and is recorded. At this time, when the output of amplifier 1 exceeds a certain level, a transistor is turned on via diode 4 and capacitor 3 to control the recording level.

In this circuit, the switch S4 must be muted.
A voltage is applied to the transistor 6 via the transistor 6.

On the other hand, when playing, S1+S! is switched in the opposite direction to that in FIG. For this reason, the playback signal of door a is switched to switch S1.
1 is applied to the output end f a via an anode 11 and a resistor 7. At this time, when the reproduction mute switch S3 is turned on, a voltage is applied to the base of the transistor 5 and the output is suppressed. The muting circuit shown in Fig. 1 is a circuit for the case where the recording AGC's timer time does not need to be shortened, and when the recording and playback muting is turned from ON to OFF, the output is output for a period of 0.5 to 3 seconds. The structure is such that capacitors 8 and 9 are provided to restore the state. On the other hand, in the conventional example shown in Figure 2 of 7.j, the recording AGC Ijp per time is set long, so that when recording and playback muting is turned from ON to OFF, it is not affected by the recording AGC recovery time. The output is configured to return immediately. The operation of the circuit is the same as that shown in Figure 1, and the same symbols as in Figure 1 represent the same contents.
is a transistor, and 13 is a resistor.

However, in this conventional configuration, separate transistors are required for recording muting and playback muting.

In order to solve these problems, the present invention provides a tape recorder with a simplified circuit configuration in which the AGC recorder circuit serves both the recording meeting and playback meeting functions.

Embodiments of the present invention will be described below with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, parts having the same functions as those in FIGS. 1 and 2, respectively, are denoted by the same reference numerals, and explanations thereof will be omitted. S3 becomes a playback mute switch during playback, and when the full voltage is applied to transistor 2 via voltage application terminal d, simulator switch, and chi S3, transistor 2 is turned on, suppressing the human power of amplifier 1 and operating as a playback mute switch. On the other hand, during recording, S3 becomes a recording mute switch, applies voltage to transistor 2 via 83, and operates as a recording mute.

As described above, the present invention allows the recording AGC circuit to be used for recording meetings and playback meetings, thereby simplifying the circuit configuration.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing a conventional example, and FIG. 3 is a circuit diagram showing a conventional example. FIG. 4 is a circuit diagram of the present invention. a... Recording/playback magnetic head, b... Input terminal, C...
...Output terminal, d...Voltage application terminal, SI+82...
・Recording/playback selector switch, S3, S4... Meeting 0 switch, ■... Recording/playback amplifier, 2, 5, 6.
...transistor, 3,8,9.12...capacitor, 4 diodes, 7.11.13...resistance.

Claims (1)

[Claims] This muting circuit for a tape recorder is equipped with an AGC recording circuit, and is characterized in that the circuit serves as a recording muting function to create unrecorded portions, and a playback muting function to lower the volume during playback.