JPH0736205B2 - Tape recorder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tape recorder suitable for recording conversations of a plurality of speakers.

2. Description of the Related Art Conventionally, portable type tape recorders are often used for music, daily conversation, and learning, and in recent years, high-definition recording mainly for conversation such as conferences, particularly clear voice of the other party. There is a demand for tape recorders that can record.

Hereinafter, a conventional tape recorder will be described with reference to the drawings. FIG. 3 is a block diagram of a recording circuit of a conventional tape recorder. In FIG. 3, 1
Is a microphone, 2 is a microphone signal amplifier, 3 is a recording current amplifier, 4 is an AGC circuit, and is an AGC amplifier 5, a time constant circuit that determines the response time of the AGC circuit, and an impedance element 7 that controls the gain of the microphone amplifier 2. It is configured. 8 is a recording equalizer circuit that determines recording characteristics via the head 10.
Reference numeral 9 is a bias oscillation circuit.

The operation of the tape recorder configured as described above will be described below. First, when the signal that has passed through the microphone signal amplifier 2 and the recording current amplifier 3 becomes higher than the specified signal level in the AGC amplifier 5, the AGC circuit 4 operates, lowers the input impedance of the microphone signal amplifier, and lowers the partial pressure of the input signal. The AGC circuit 4 operates so as to be balanced at the specified signal level. At this time, the AGC recovery time is uniquely determined, and the frequency characteristic of the recording equalizer circuit is also uniquely set. The AGC recovery time is usually relatively long, set at 2-8 seconds.

Problems to be Solved by the Invention However, in the above configuration, the tape recorder 23 is used as shown in FIG.
When recording a conversation between a speaker A close to the speaker A and a speaker B slightly distant from the speaker A, first the speaker A's voice is recorded by the speaker A's voice.
Even after C is activated and speaker A's voice is ended, speaker B's voice is recorded at a low recording level because the gain of the microphone signal amplifier is suppressed during the AGC recovery time. On the other hand, the speaker B has a drawback in that it is always recorded at a low level and cannot sufficiently serve the purpose of clearly recording the strangeness of the other party as a conversation recording. Further, the speaker B is farther than the speaker A with respect to the tape recorder.
As shown in the figure, in addition to the output difference due to distance, the signal output to the microphone lowers the low frequency component of the signal due to the fact that the microphone is placed at the so-called off microphone position, and sensitivity deterioration at the low frequency is multiplied. However, the recording is biased to high frequency components, the recorded and reproduced sounds are kinky voice recordings, and the recorded sounds of distant sounds have the drawback of being poor in clarity.

The present invention solves the above-mentioned problems, and makes it possible to select the AGC recovery time of the AGC circuit, the frequency characteristic of the recording equalizer circuit, and the recording level by switching a switch.

Means for Solving the Problems In order to solve the above problems, the tape recorder of the present invention is configured so that when the voice by the speaker close to the tape recorder is interrupted, the voice of the other party can be awaited at the maximum sensitivity state almost at the same time. Switching circuit of the time constant circuit that shortens the recovery time, switching circuit that switches the correction circuit of the attenuated low frequency component of the frequency component of the distant voice of the other party, and a display that clearly indicates that these circuits have been switched A circuit and a switch circuit for switching the switching circuit and the display circuit are provided.

Effect The present invention, by the above-mentioned configuration, simultaneously performs AGC recovery time switching, recording equalizer switching, and recording level switching, and by simultaneously switching the display circuit that displays this switching state, recording during conversation can be performed. The voice of the other party can be recorded more clearly and clearly.

Embodiment Hereinafter, a tape recorder according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram and a functional circuit of a tape recorder in an embodiment of the present invention, and the same reference numerals as those in FIG. 3 show the same components.

1 is different from FIG. 3 in that the AGC circuit 4 is
The switch 13 with the resistor 14 added to the time constant circuit 6
The recording equalizer circuit 8 is provided with two filter circuits so as to be switched by the switch 13, and the display circuit 15 is additionally provided so as to be switched by the switch 13.

Regarding the tape recorder configured in this way,
The operation will be described with reference to FIG.

First, the recording of the microphone signal passes through the microphone signal amplifier 2 and the recording current amplifier 3, one side is recorded in the AGC circuit 4, and the other side is recorded through the recording equalizer circuit 8 and the head 10 to record the recording signal on the tape. Here, the time constant circuit 6 for changing the AGC recovery time in the AGC circuit 4 has a time constant switching resistor 14 connected to the terminal 11a of the changeover switch 11, and this resistor 14 is connected to the terminal 11a of the switch 11. The time constant is short when it is grounded through, therefore, by shortening the recovery time, the microphone signal amplifier 2 can be returned to the maximum gain almost at the same time when the voice of the speaker A near the tape recorder ends.

As a result, the voice of the speaker B can be recorded as a loud voice without being suppressed. At this time, the recovery time is 0
Aim for 200mS or less. In addition, the switch 12 provided in the recording equalizer circuit 8 in conjunction with the switch 11 is connected to the terminal.
Switch from 12b to terminal 12a. The recording equalizer circuit 8 has a normal characteristic as shown by the equalizer 20 connected to the terminal 12b as shown in FIG. 2, and the equalizer connected to the terminal 12a has a low frequency range as compared with the mid range as shown by 19. About 3-6d
2 to 4 compared to normal characteristics in the mid range as well as raising B
The characteristics are raised by dB. Therefore, the voice of the speaker B during the conversation, that is, the recording is performed so as to correct the state where the speaker B is far from the microphone (off-microphone state), and a natural recording characteristic with higher clarity can be obtained.

Further, the recording equalizer circuit 8 records at a higher recording level even in the middle range, so that the voice of the speaker A is AGC.
Speaker B who is far away even if the level is low
Is set to be recorded loud. Therefore, when the switches 11 and 12 are in the terminals 11a and 12a, a relatively large amount of sound is recorded when the voice of the speaker B is recorded, regardless of the input level of the input signal.

Further, when the switch 11 is turned on to the terminal 11a, the display LED lighting circuit 15 operates, the LED 16 is turned on, and when the switch 11 is turned on to the terminal 11b, the LED is turned off.

As described above, according to the present invention, by changing the switch, it is particularly preferable that the position of a recording state where a signal is unidirectionally input in music or the like and the change of the input signal level such as conversation is large in normal recording. It is said that it is possible to select a position in a recording state for the purpose of clearly recording a distant voice clearly, and at the same time, select a frequency characteristic and a recording level of a recording equalizer circuit, thereby making it possible to clarify conversation recording. There are advantages.

[Brief description of drawings]

FIG. 1 is a block diagram of a tape recorder in one embodiment of the present invention, FIG. 2 is a frequency characteristic diagram of a recording equalizer circuit of the tape recorder, and FIG. 3 is a block circuit diagram of a conventional tape recorder. FIG. 4 shows a recording state of a conventional tape recorder, b is a frequency characteristic diagram, b is an explanatory diagram of a signal output difference depending on the distance of the speaker to the microphone, and FIG. 5 is a diagram of the speaker and the tape recorder during conversation. It is a relative relationship diagram. 2 ... Microphone amplifier, 3 ... Recording current amplifier, 4 ... AG
C circuit, 8 ... recording equalizer circuit, 15 ... display circuit, 1
1,12 …… Switch.

Claims (1)

[Claims] 1. A switching circuit for shortening the recovery time of an automatic gain control circuit for automatically controlling the gain of a microphone signal of a microphone recording circuit, and a switching circuit for compensating for the low frequency range frequency characteristic of a recording compensation circuit and raising the recording level. A tape recorder comprising a display circuit that clearly indicates this switching and a switch circuit that simultaneously switches these switching circuit and display circuit.