JPS6339987B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape recorder with a radio receiver, which uses an automatic gain control circuit even when listening to the radio to reduce the level difference between tape playback and radio listening.

FIG. 1 is a circuit diagram of a conventional tape recorder with a radio receiver. First, when listening to radio, a signal input from an antenna 1 is tuned and detected by a radio circuit 2, and output as a low frequency signal. The output of the radio circuit 2 is attenuated by attenuation resistors 3 and 4 to a level that adapts to the gain of the subsequent stage amplifier circuit, and the attenuated signal is sent to the preamplifier 5 through the fixed terminal b and movable terminal c of the tape radio selector switch _S1 . and is amplified here. The output of the preamplifier 5 is level-adjusted by a volume controller 6 and input to a power amplifier 7, and the output drives a speaker 8 to produce sound, which can be listened to.

Next, for tape playback, by switching the tape radio selector switch _S1 , the playback signal taken out by the head 9 is transferred to the playback terminal a of the recording/playback selector switch _S2 , the fixed terminal b, and the tape radio switch _S1.
preamplifier 5 through fixed terminal a and movable terminal c.
and is amplified here. And the output of the preamplifier 5 is the volume adjuster 6, the power amplifier 7
The speaker 8 is driven through the speaker 8, and the tape playback sound can be heard from the speaker 8.

To record a microphone signal, the tape radio selector switch _S1 is switched to the fixed terminal a side, and the recording/playback selector switches _S2 and _S3 are switched to the recording terminal c side. As a result, the microphone signal input to the microphone jack 10 is input to the preamplifier 5 through the recording terminal c and fixed terminal b of the recording/playback switch _S2 , and the fixed terminal a and movable terminal c of the radio tape switch _S1 . Ru. In this case, the preamplifier 5 functions as a recording amplifier, and its output is supplied to a recording circuit and recorded on tape by a recording head (not shown).

The output of the preamplifier 5 is input to the automatic gain control circuit 11 via the recording terminal c and fixed terminal b of the recording/playback switch _S3 , and the output thereof is supplied to the input side of the preamplifier 5 to perform automatic gain control. As a result, the gain of the preamplifier 5 is varied according to the level of the input signal input to the preamplifier 5, so that the recording signal level does not exceed a certain level.

Incidentally, when recording a radio signal, the radio tape changeover switch _S1 is switched to the fixed terminal b side, and the recording/playback changeover switches _S2 and _S3 are switched to the recording terminal c side. That is, the radio signal input to the antenna 1 is input to the preamplifier 5, the output of which is supplied to the recording circuit, and the radio signal is recorded onto the tape from the recording head. Also in this case, the output level of the preamplifier 5 is controlled by the automatic gain control circuit 11.

Here, when comparing the output levels of the preamplifier 5 in each of the above states, the output levels of the preamplifier 5 are almost the same level because the automatic gain control circuit 11 works for microphone signal recording and radio signal recording. As a result, their playback levels are approximately the same. However, when listening to the radio, the automatic gain control circuit 11 is in a non-operating state.
Moreover, since there are differences in the degree of modulation of each broadcast station, and wideband FM receivers are capable of receiving the audio of television broadcasts, the output level of the preamplifier 5 varies.

Therefore, when listening to the radio, a level difference occurs between the sound and other tape playback sounds, and if these conditions are often repeated, the volume must be adjusted each time. The quality was very bad.

The present invention solves these conventional disadvantages, and one embodiment thereof will be described below with reference to FIG. 2.

In FIG. 2, the same parts as the conventional circuit components shown in FIG. Reference is made to the above explanation regarding.

In the embodiment of the present invention shown in FIG. 2, a switch _S4 is provided which is interlocked with the radio tape changeover switch _S1 , and the fixed terminal a of this switch _S4 is left blank, and the fixed terminal b
is connected to the input side of the automatic gain control circuit 11, and the movable terminal c is connected to the output side of the preamplifier 5.

With the above configuration, even when listening to the radio with the movable terminal c of the radio tape selection switch _S1 switched to the fixed terminal b side, the output of the preamplifier 5 is routed through the movable terminal c and the fixed terminal b of the switch _S4 . The signal is input to the automatic gain control circuit 11, and the automatic gain control circuit 11 operates to control the output level of the preamplifier 5.

Therefore, when listening to the radio, the output level of the preamplifier 5 is controlled by the automatic gain control circuit 11 in the same way as when recording a microphone signal or a radio signal, so that the preamplifier 5 in each of these operating states The output levels are almost the same, and even if these operations are repeated often, there is almost no difference in level, eliminating the need for volume adjustment operations.

As is clear from the above embodiments, the present invention provides a preamplifier that amplifies microphone signals, radio signals, etc. when recording these signals, and also amplifies the radio signals when listening to the radio, and controls the output level of the preamplifier. An automatic gain control circuit is provided, and a switch is provided that operates in conjunction with a radio tape selection switch provided on the input side of the preamplifier, and when the radio tape selection switch is in the radio position, the switch operates the automatic gain control circuit. By controlling the automatic gain control circuit to be in the state, the automatic gain control circuit is configured to operate both when recording microphone signals and radio signals and when listening to the radio.According to the present invention, in particular, There is almost no difference between the playback level of a tape recording microphone signal and radio signal and the level when listening to radio, so even if there is a difference in the modulation degree of each broadcast station when listening to radio, or when receiving television broadcasts, It is not necessary to adjust the volume each time a broadcast is received, and therefore it is extremely useful in terms of operability compared to conventional tape recorders of this type, and its effects are great.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional tape recorder with a radio receiver, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. 1...Antenna, 2...Radio circuit, 5...Preamplifier, 8...Speaker, 9...Head, 10
... Microphone jack, 11 ... Automatic gain control circuit, S ₁ ... Radio tape selection switch, S ₂ ,
_S3 ...Recording/playback switch, _S4 ...Switch.

Claims (1)

[Claims] 1. A preamplifier that amplifies microphone signals, radio signals, etc. during recording, and also amplifies tape playback signals and radio signals when listening to the radio; an automatic gain control circuit that controls the output level of this preamplifier; The automatic gain control circuit is operated in conjunction with a radio tape selection switch provided on the input side for switching between a radio signal and a microphone signal or a tape playback signal, and when the radio tape selection switch is in the radio position, the automatic gain control circuit is activated. and a recording/playback switch installed in parallel with the changeover switch so as to activate the automatic gain control circuit when recording microphone signals, radio signals, etc. and is configured to operate during both recording and listening to radio signals, etc., to reduce the level difference between the playback sound of a recording tape such as a microphone signal and radio signal, and the preamplifier output when listening to the radio. A tape recorder with a radio receiver.