JPS6243908A - Amplifier - Google Patents

Abstract

PURPOSE:To optimize the sound volume setting to the next stage and to easily cope with an input signal at a wide range by interlocking the 1st stage amplifier gain setting circuit and a sound adjusting device. CONSTITUTION:A signal from an audio input terminal 15 is amplified at the 1st stage amplifier 11 by the gain decided at the 1st stage amplifier gain setting circuit 12. In this case, an interlocking sound adjusting device 13 having an optimum change characteristic is interlocked with a variable resistor of the circuit 12. Since the interlocking sound adjusting device and the 1st stage amplifier gain setting circuit are interlocked in this way to make the characteristic variable, the distortion at the 1st stage is prevented, the sound volume setting to the next stage is optimized to cope with a wide variety of input level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for amplifying audio input signals.

BACKGROUND OF THE INVENTION FIG. 3 is a block diagram of an input amplification device in a conventional audio mixer. In the figure, 1 is an input attenuator (pad), 2 is a first-stage amplifier, 3 is a gain adjuster for the first-stage amplifier, 4 is an input level indicator, 6 is a volume adjuster, and θ is a buffer amplifier. When inputting a signal from the audio input terminal shown in the figure, depending on the level, input attenuator 1 is turned on or off to input 2, so that the signal is input to first stage amplifier 2 at a level that does not cause distortion in first stage amplifier 2. do.

The gain of the first stage amplifier 2 is set by the first stage gain adjuster 3 so that the input level indicator 4 does not light up.

The signal amplified by the first stage amplifier 2 is adjusted by a volume adjuster 5 and then amplified by a buffer amplifier 6, and then output to an audio output terminal 8.

The transition of these signal levels will be explained with reference to FIG.

When the audio input is input to the (a) area at the maximum level, it is amplified by the first stage amplifier 2 in the (b) area, and the input level indicator 4 in the (b) area indicates that the audio signal does not enter the clipping area where it is distorted. After setting the level through the volume adjuster 6 in the (E) area while being monitored to ensure that the
It is amplified by the buffer amplifier 6 in the region (g) to reach the output level of the region. The level transition of the system is the case where the maximum level is amplified without using the input attenuator 1. In this case, the first-stage amplifier 2 amplifies in the region (c), but the input indicator 6 remains lit until the clip level is reached and distortion occurs, making it impossible to change as shown by the thick line a, and at the same time reaching the clip level. The output of -1- can be obtained in the (g) area (- cannot be obtained. Therefore, the level transition of B is as follows ('). 1) The output it, (g) area (″),
1: Maximum output is obtained. In the level transition of C, a normal input is obtained and a normal output is obtained with the input attenuator 1 left ``off'' even in the (b) region.

Problems to be solved by the invention are as follows: 1) In the conventional example, the input attenuator 1,
First stage gain adjuster 3. For each adjustment of the volume adjuster 6, the first stage gain adjuster 3 adjusts the amplification level of the first stage amplifier 2, and the input attenuator 1 adjusts the input level to such an extent that the input level indicator 4 does not light up continuously. [7.Furthermore, the drawback is that it requires complicated level balance settings, in which the volume adjuster 6 is used to set the level of the audio output to the next stage so that the signal-to-noise ratio is also advantageous. In the conventional method, the maximum input level to the first-stage amplifier 3 is severely limited, and unless several types of attenuation amounts for the input attenuator 1 and gains for the first-stage amplifier 2 are prepared, the required maximum input level cannot be received.C) No, the drawback is that the circuit configuration becomes more complicated.)
Na.

The present invention has a single stage to solve the problem.The first stage amplifier gain (the gain is adjusted by one 5i1 circuit and the maximum input level that can be received by the first stage) can be increased by 17,
And volume adjuster and first stage amplifier benefit 1! I setting 51"" This is to make the circuit have the optimum change characteristics and make it interlock.
Since the characteristics are made variable in conjunction with the setting circuit, it is possible to prevent distortion in the first stage, optimize the volume setting for the next stage, and accommodate a wide range of human power levels.

EXAMPLE An example of the present invention will be described below with reference to the drawings. In FIG. 3, this is the audio input terminal to the 1 esll first-stage amplifier, and the input signal is sent to the interlocking volume adjuster 13 through the first-stage amplifier 11, and its output is passed through the buffer amplifier 14 to the audio output terminal 16. Supplied.

The following embodiment will be described in further detail. In Figure 3,
The signal from the audio input terminal 5 is amplified in the first stage amplifier 11 with a gain determined by the first stage amplifier gain setting circuit 12. At this time, the first stage amplifier gain setting circuit 12
By interlocking with the variable resistor, it is possible to set the optimum level of the input signal to the next stage buffer amplifier 14, and with a single volume reduction, it is possible to set the gain of the first stage and adjust the optimal volume to the next stage. become.

Next, the level transition when the above operation is performed will be explained with reference to FIG. The region (b) indicates the level range at which the audio input signal is input to the first stage amplifier 11. In the (b) area, the gain is set corresponding to a wide range of audio input levels by the gain setting of the first stage amplifier 11, and in the (c) area, the interlocked volume adjuster 13 is linked to the gain setting in the ←) area. Set the volume to the optimal level for the next stage. In the region (b), the buffer amplifier 14 buffer-amplifies the signal at the set level in the region (c). In the (e) area, the name is output from the buffer amplifier 14 to the audio output terminal 16 as an audio output signal.

In this embodiment, the first stage gain can be set based on one volume level, and the optimal volume adjustment for the next stage can be performed, so that the following effects can be obtained.

(a) When the signal level of the audio input is high, the gain of the first-stage amplifier can be lowered by the interlocking volume adjuster, which prevents distortion due to excessive input in the first-stage amplifier and provides an appropriate buffer amplifier for the next-stage amplifier. You can set the output level.

(b) When the signal level of the audio input is low, the gain of the first stage amplifier can be increased by the interlocking volume adjuster, so the signal level in the signal-to-noise ratio is increased and the signal is sent to the buffer amplifier. This allows the next-stage amplifier to receive the signal at an appropriate input level and with the most advantageous signal-to-noise ratio.

(0) When the input level indicator and indicator for monitoring excessive input in the first stage amplifier, which were conventionally required, are lit, the gain of the first stage amplifier 71, -2 is reduced in response. The complicated work of moving the adjuster and adjusting the level balance with the volume adjuster in front of the buffer amplifier can be done by adjusting only the interlocking type volume adjuster to achieve the optimal level balance before and after the buffer amplifier.

((1) The gain adjuster and input level indicator of the first-stage amplifier are no longer required, and the optimal level balance can be achieved using only the interlocking volume adjuster, which simplifies the circuit configuration of the implementation device, reduces costs, and improves operation. The panel section can be made smaller and the operation can be simplified.

(+5) Gain setting and volume adjustment are linked using a variable resistor. This allows for a wide range of applications since it is possible to combine the optimum change characteristics for the circuit conditions.

(A wide range of input levels can be accommodated by changing the gain of the first stage amplifier.

Effects of the Invention According to the amplifier of the present invention, since the first stage amplifier gain setting circuit and the volume adjuster are linked, the volume setting for the next stage can be optimized and it can easily handle input signals of a wide range of levels. can do.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an amplifying device according to an embodiment of the present invention, and FIG. 2 is a level transition diagram thereof. FIG. 3 is a program diagram showing an example of a conventional amplifying device, and FIG. 4 is a level transition diagram thereof. 11... First stage amplifier, 12... First stage amplifier gain setting circuit, 13... Volume adjuster, 14
...Buffer amplifier. Name of agent: Patent attorney Toshio Nakao (1st person)
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Claims (1)

[Claims] An amplifier device comprising a first-stage amplifier circuit, a first-stage amplifier gain setting circuit, and a volume adjuster, and in which gain setting by the first-stage amplifier gain setting circuit and volume adjustment by the volume adjuster are linked.