JPH1049609A - Mean n-th power device and amplitude compressing/ extending device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smooth the switching of a gain, and to clearly change the switching by using a mean N-th power means for a method for synthesizing a control signal. SOLUTION: Rectified currents |I6| of input currents inputted to a signal synthesizer 100 are compared with currents I8 from a current source, and when the input currents are smaller, an output voltage V2 is turned into a constant gain area in proportion to the size of an input voltage V1, and set by the currents I8. On the other hand, when the input currents are larger, the output voltage V2 is turned into a constant voltage output area for outputting a constant voltage regardless of the size of the input voltage V1. Thus, the switching of the gain of a output voltage characteristic from the constant gain area to the constant voltage output area can be clearly changed by control currents I3 obtained by N-power averaging and synthesizing the inputs of the rectified currents |I6| being an input signal inputted to the signal synthesizer 100 and the currents I8 of the current source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ALC (automatic level control) device and an amplitude compression / expansion device for processing signals such as audio and video, and more particularly to an N-mean-square device and an amplitude compression / expansion device using the same. Things.

[0002]

2. Description of the Related Art Conventionally, a compander (amplitude compression / expansion) apparatus described in Philips Semiconductor Data Handbook NE / SA572 has been generally used as this kind of apparatus. Figure
13 shows a case where Philips NE / SA572 of the United States is configured as an ALC device, FIG. 15 shows a compressor device, and FIG.
FIG. 4 is a block diagram showing a case where the configuration is an expander device.

The ALC device shown in FIG. 13 can suppress distortion by lowering the gain only when the input signal becomes larger than a set value. Further, by combining the compressor device shown in FIG. 15 and the expander device shown in FIG. This is useful for securing a dynamic range in audibility even in signal transmission through a narrow dynamic range.

[0004] The configuration and operation will be described below with reference to the drawings. FIG. 13 is a block diagram showing the configuration of an ALC device. In FIG. 13, reference numeral 1 denotes a signal input terminal;
2 is a signal output terminal, 3 is a control terminal for controlling the gain of the ALC device, and 4 is an input voltage V of a signal applied to the input terminal 1.
A voltage-current converter 5 for converting 1 into a current and inputting it to a gain conversion amplifier, which will be described later;
Reference numeral 6 denotes a voltage-current converter that converts an input voltage V1 of a signal applied to the input terminal 1 into a current and inputs the current to a rectifier described later.
Is configured to handle the input and output of signals with current,
A rectifier whose input is a virtual ground point, 8 is a current source of a current I8 input from the control terminal 3, and 9 is a current source of a current I8 of the current source 8.
And a rectifier current | I6 | output from the rectifier 7, and a mixer 10 that outputs a control current I3 of the variable gain amplifier 5,
This is a current-voltage converter that converts the output current I2 of the variable gain amplifier 5 into a voltage and includes an amplifier 10a and an impedance 10b.

The variable gain amplifier 5 functions as a divider for dividing the input current I1 by the control current I3 from the mixer 9. FIG. 14 is a diagram showing the relationship between the input voltage V1 and the output voltage V2 in the configuration of FIG.

Next, FIG. 15 is a block diagram showing a configuration of a compressor device for outputting a voltage proportional to a half power of an input signal, in which a control signal is obtained from an output voltage V2. FIG. 16 is a block diagram showing a configuration of an expander device that outputs a voltage proportional to the square of an input signal. The configuration is such that a control signal is obtained from the input voltage V1, and the variable gain amplifier 5 mixes the input current I1. It functions as a multiplier for multiplying by the control current I3 from the unit 9.

Further, by combining the compressor device shown in FIG. 15 and the expander device shown in FIG. 16, a compander device in which the input voltage and the output voltage finally have a proportional relationship can be constituted. Further, in FIGS. 15 and 16, components corresponding to those described with reference to FIG. 13 are denoted by the same reference numerals, and redundant description thereof will be omitted.

Next, the operation of the ALC apparatus shown in FIG. 13 will be described. Now, assuming that the input voltage V1 is applied to the input terminal 1, the input of the variable gain amplifier 5 is at the virtual ground point. Converted to I1.

[0009]

(Equation 1)

Here, Z4: conversion coefficient of the voltage / current converter 4 The converted input current I1 is input to the variable gain amplifier 5.

The input of the rectifier 7 is also at a virtual ground point, and the input voltage V1 is converted into a current I6 by the voltage / current converter 6, and further rectified by the rectifier 7.
The rectified current | I6 | as shown in (Equation 2) is input to the mixer 9.

[0012]

(Equation 2)

However, Z6: the conversion coefficient of the voltage-current converter 6 The mixer 9 outputs a control current I3 obtained by adding the current I8 from the control terminal 3 and the rectified current | I6 | of the rectifier 7. And is expressed by (Equation 3).

[0014]

I3 = | I6 | + I8 On the other hand, the variable gain amplifier 5 functions as a divider for dividing the input current I1 by the control current I3 from the mixer 9 as a control signal. I1
Is input and the control current I3 is input as a control signal, the output current I2 of the variable gain amplifier 5 becomes as shown in (Equation 4).

[0015]

(Equation 4)

The output current I2 of the variable gain amplifier 5 is
The output voltage V2 of the amplifier 10a is input to the virtual ground point of the current-voltage converter 10 forming a negative feedback circuit by the amplifier 10a and the impedance 10b.
The output voltage V2 is obtained by multiplying the output current I2 by the impedance 10b, and is represented by (Equation 5).

[0017]

(Equation 5)

Here, Z10: the conversion coefficient of the current-voltage converter 10, where the signal input to the input terminal 1 is sufficiently small and the rectified current | I6 | is sufficiently smaller than the current I8, that is, | V1 | / Z6}. In the case of I8, | V1 of the denominator of (Equation 5)
| / Z6 can be ignored, and the relationship between the input voltage V1 and the output voltage V2 is as shown in (Equation 6).

[0019]

(Equation 6)

Accordingly, when the input voltage V1 is small, that is, when | V1 | / Z6≪I8, the output voltage V2 is proportional to the magnitude of the input voltage V1, and the gain at that time is Z10 / (Z4 × I8).

When the signal input to the input terminal 1 is sufficiently large and the rectified current | I6 | is sufficiently larger than the current I8, that is, when | V1 | / Z6≫I8, I8 in the denominator of (Equation 5) is It can be ignored, and the relationship between the input voltage V1 and the output voltage V2 is as shown in (Equation 7).

[0022]

(Equation 7)

As a result, when the input voltage V1 increases, that is, when | V1 | / Z6≫I8, the magnitude of the output voltage V2 becomes independent of the magnitude of the input voltage V1, and the voltage-current converters 4, 6, Conversion coefficients Z4, Z of current-voltage converter 10
6, Z10.

FIG. 14 is a diagram obtained from (Equation 6) and (Equation 7).
13 shows characteristics of the input voltage V1 and the output voltage V2 in the configuration of FIG.

As described above, the rectified current | I6 | proportional to the input voltage and the current I of the current source 8 input from the control terminal 3
8 is input to the variable gain amplifier 5 as a control signal, and the variable gain amplifier 5 is caused to function as a divider, so that when the input voltage V1 is small, the output voltage V2 becomes
As obtained by (Equation 6), the voltage increases in proportion to the magnitude of the input voltage V1, and the gain at that time is set by Z10 / (Z4 × I8). On the other hand, when the signal input to the input terminal 1 becomes sufficiently large, the magnitude of the output voltage V2 becomes irrelevant to the magnitude of the input voltage V1 as determined by (Equation 7), and the voltage-current converters 4, 6 , The conversion coefficient Z of the current / voltage converter 10
A, which becomes a constant voltage output determined by 4, Z6 and Z10
An LC device can be configured.

Next, the operation of the compressor device shown in FIG. 15 in which a part of the control signal is obtained from the output voltage V2 will be described.

If the input voltage V1 is applied to the input terminal 1, the input of the variable gain amplifier 5 is at the virtual ground point. Therefore, the input voltage V1 is calculated by the voltage / current converter 4 as shown in (Expression 8). Is converted to the input current I1.

[0028]

(Equation 8)

Z4: conversion coefficient of the voltage / current converter 4 The converted input current I1 is input to the variable gain amplifier 5.

The input of the rectifier 7 is also at a virtual ground point, and the output voltage V2 is converted to a current I6 by the voltage-current converter 6, and further rectified by the rectifier 7 to obtain a rectified current | I6 | and input to the mixer 9.

[0031]

(Equation 9)

However, assuming that nothing is connected to the control terminal 3 for controlling the conversion coefficient gain of the voltage-to-current converter 6, the control current I 3 output from the mixer 9 becomes the rectified current | I 6 | Is output as it is, and is expressed by (Equation 10).

[0033]

I3 = | I6 | On the other hand, the variable gain amplifier 5 functions as a divider for dividing the input current I1 by the control current I3 from the mixer 9 which becomes a control signal. The output current I2 is as shown in (Equation 11).

[0034]

[Equation 11]

The output current I2 of the variable gain amplifier 5 is
The output voltage V2 of the amplifier 10a is input to the virtual ground point of the current-voltage converter 10 forming a negative feedback circuit by the amplifier 10a and the impedance 10b.
And the output voltage V2 obtained by multiplying the output current I2 by the impedance 10b, and is represented by (Equation 12).

[0036]

(Equation 12)

As a result, the output voltage V2 is proportional to the half power of the input voltage V1, and the characteristic that the level width of the input signal is compressed to half the decibel is obtained.

As described above, the control signal is obtained from the output voltage V2, so that the output voltage V2 becomes the input voltage V2.
It becomes proportional to 1 1/2 power, and it is possible to configure a compressor device for compressing the input signal level width to 1/2 times in decibels.

The control signal shown in FIG.
The operation of the expander device having the configuration obtained from 1 and functioning as a multiplier in which the variable gain amplifying device 5 multiplies the input current I1 by the control current I3 from the mixer 9 will be described.

Now, assuming that the input voltage V1 is applied to the input terminal 1, the input of the variable gain amplifier 5 is at a virtual ground point. Is converted to the input current I1.

[0041]

(Equation 13)

The converted input current I 1 is input to the variable gain amplifier 5.

The input of the rectifier 7 is also at a virtual ground point, and the input voltage V1 is converted into a current I6 by the voltage-current converter 6, and further rectified by the rectifier 7 (Equation 1).
The rectified current | I6 | is input to the mixer 9 as shown in 4).

[0044]

[Equation 14]

Assuming that nothing is connected to the control terminal 3 for controlling the gain, the control current I3 output from the mixer 9 outputs the rectified current | I6 | as it is. Will be represented by

[0046]

I3 = | I6 | The variable gain amplifier 5 functions as a multiplier for multiplying the input current I1 by the control current I3 from the mixer 9 which becomes a control signal. When I1 is input and the control current I3 is input, the output current I2 of the variable gain amplifier 5 becomes as shown in (Equation 16).

[0047]

(Equation 16)

The output current I2 of the variable gain amplifier 5 is
The output voltage V2 of the amplifier 10a is input to the virtual ground point of the current-voltage converter 10 forming a negative feedback circuit by the amplifier 10a and the impedance 10b.
The output voltage V2 is obtained by multiplying the output current I2 by the impedance 10b, and can be expressed by (Equation 17).

[0049]

[Equation 17]

Thus, in the configuration of FIG. 16, the relationship between the input voltage V1 and the output voltage V2 is such that the output voltage V2 is proportional to the square of the input voltage V1, and the input signal level width is doubled in decibels. Characteristics are obtained.

As described above, the control signal is obtained from the input voltage V1 and the variable gain amplifier 5 functions as a multiplier, so that the output voltage V2 is proportional to the square of the input voltage V1. Level width 2 in decibels
An expander device that doubles can be configured.

The compressor shown in FIG. 15 and the compressor shown in FIG.
By combining the described expander devices, even in the signal transmission through a narrow dynamic range, the signal level width is compressed to 1/2 by a compressor before transmission, and the signal level width is expanded to 2 times by an expander after transmission, so that the audibility can be improved. A compander device that can secure the above dynamic range can be configured.

[0053]

However, in the device having such a conventional configuration, the rectified current | I6 | proportional to the input voltage V1 for controlling the gain of the ALC device and the current of the current source input from the control terminal are provided. In I8, the rectified current |
Switching to a region where I6 | is dominant and controls and a region where the current I8 of the current source is dominant and controls the gain, that is, from | V1 | / Z6≫I8 |
When switching the control signal to V1 | / Z6≪I8, there is a first problem that the switching of the gain of the variable gain amplifier does not change clearly.

When an ALC function such as reducing the gain and suppressing distortion is added to the compressor circuit only when the input signal becomes larger than the set value, the compressor circuit shown in FIG. There is a second problem that it is necessary to provide the described ALC devices in series and the circuit becomes large-scale.

The present invention solves the above-mentioned problem of the prior art. In the first problem, the rectified current | I6 | The switching of the gain by the current I8 of the source is smooth and the switching is a clear change.

In the second problem, the method of synthesizing the control signal of the compressor shown in FIG. 15 employs an N-th power averaging means, and has an ALC function only by adding a rectifier and a voltage-current converter. It is an object of the present invention to provide an N-th power averaging device that can constitute a compressed compressor device and an amplitude compression / expansion device using the same.

[0057]

In order to achieve this object, in an N-mean averaging apparatus according to the present invention and an amplitude compression / decompression apparatus using the same, the N-mean averaging apparatus comprises a first signal for raising the first signal to the Nth power. N-th power means, second N-th power means for raising the second signal to the N-th power, and N-th power means for mixing the first N-th power signal and the second N-th power signal to obtain an N-th power And

Further, a first N-th means in which n number of transistors for raising the first signal current to the Nth power are connected in series, and a second means for connecting the number N of second signal currents to the Nth power in series are connected. 2 N power means, (n-2) series connected transistors, a first transistor having a base connected to the first N power means, a collector connected to the power supply voltage, an emitter connected to the transistor group, The second N-th power means includes a second transistor having a base connected to the power supply voltage, a collector connected to the power supply voltage, and an emitter connected to the transistor group, and a current mirror circuit that uses an input from the transistor group as an output of the device.

Further, m Nth means in which n transistors for raising the signal current to the Nth power are connected in series, (n-2) transistors connected in series, a base and power supply voltage And a current mirror circuit that uses the input from the transistor group as the output of the device, and the m transistors having the collector and the emitter connected to the transistor group.

Further, the amplitude compression / expansion device includes a variable gain amplifying means for varying the gain of the input signal by a control signal, a rectifying means for rectifying the input signal, and an N-mean square of an output signal of the rectifying means and an external control signal. And a signal synthesizing means for synthesizing and outputting a control signal.

Further, a variable gain amplifying means for varying the gain of an input signal by a control signal, a rectifying means for rectifying an output signal of the variable gain amplifying means, and an N-square average of an output signal of the rectifying means and an external control signal. And a signal synthesizing means for synthesizing and outputting as a control signal.

Further, variable gain amplifying means for varying the gain of an input signal by a control signal, first rectifying means for rectifying the input signal, second rectifying means for rectifying the output signal of the variable gain amplifying means, A signal synthesizing unit for performing an N-th power averaging and synthesizing the output signal of the first rectifying unit and the output signal of the second rectifying unit, and outputting the resultant as a control signal;

Further, variable gain amplifying means for varying the gain of the input signal by the control signal, first rectifying means for rectifying the input signal, second rectifying means for rectifying the output signal of the variable gain amplifying means, The output signal of the first rectifier, the output signal of the second rectifier, and an external control signal are averaged to the N-th power and synthesized, and the resultant signal is output as a control signal.

According to the above configuration, the input signal can be averaged by the N-th power, and similarly, the m-th input can be output by averaging the N-th power.

Further, the switching of the gain of the amplitude compression / expansion device can be made smooth and the switching can be made a clear change by the control signal that combines the input or output signal and the external control signal by N-th power averaging.

Further, a compressor device having an ALC function can be constructed by combining the input signal and the output signal as a control signal by averaging them by the N-th power.

Further, by combining the input signal, the output signal, and the external control signal as a control signal by N-th power averaging and combining them, it is possible to switch the gain of the amplitude compression / expansion apparatus in three stages.

[0068]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a specific configuration diagram of the N-th power average device according to the first embodiment of the present invention. In FIG. 1, reference numerals 11 to 1n denote n series-connected diode-connected transistors constituting first N-th power means, and reference numerals 21 to 2n denote n series-connected diode-connected transistors which constitute second N-th power means. The transistor, 31 has a first N
A first transistor having a base connected to the base of the transistor 11 of the multiplying means and a collector connected to the power supply voltage Vcc;
32 is a second transistor having a base connected to the base of the transistor 21 of the second N-th power means and a collector connected to the power supply voltage Vcc, and (n-2) 42 to 4 (n-1) are connected in series. A connected diode-connected transistor, 50 is a current mirror circuit constituted by a transistor 51 forming a current mirror with the transistor 4n, and 52 is a transistor
A collector 51, a current output terminal; 61, a current input terminal of the first N-th power means; 62, a current input terminal of the second N-th power means;
Denotes a first current source, and 602 denotes a second current source.

In the first embodiment, the first input current and the second
, Which is composed of a first N-th power circuit (N-th power means) and a second N-th power circuit.
(N-th power means) and an N-th power average circuit (N-th power means) for averaging the outputs of the first N-th power circuit and the second N-th power circuit. The N-th power circuit includes a first N-th power circuit composed of a first current source 601 and transistors 11 to 1n, and a second current source 6
02 and a second N-th power circuit composed of transistors 21 to 2n. The N-mean-square circuit includes a first transistor 31, a second transistor 32, and a first transistor.
The emitter of the transistor 31 and the second transistor 32 are connected to each other, and the transistors 42 to
4 (n-1), and a current mirror circuit 50 composed of a transistor 4n and a transistor 51. The collector of the transistor 51 is used as an output.

Now, the input current I is supplied to the first current input terminal 61.
When 601 is input, the terminal voltage V61 of the current input terminal 61 becomes
Diode-connected transistors 11 to n connected in series
It is the sum of the base-emitter voltages of 1n and is expressed by (Equation 18).

[0071]

(Equation 18)

Where Is is the reverse saturation current value of the transistor. On the other hand, when the input current I602 is inputted to the second current input terminal 62, the terminal voltage V62 of the current input terminal 62 becomes n diode-connected transistors connected in series. The sum of the base-emitter voltages of 21 to 2n is expressed by (Equation 19).

[0073]

[Equation 19]

The terminal voltages V61 and V62 become the input voltages of the N-th power average circuit, and are connected to the bases of the first transistor 31 and the second transistor 32, respectively.

At this time, if the collector currents of the first transistor 31 and the second transistor 32 are Ic31 and Ic32, respectively, and the current flowing into the transistor group of the transistors 42 to 4 (n-1) is Ic42, Ic31 and Ic32 The relationship between the current Ic4 flowing into the transistor 42 is given by Kirchhoff's current law, assuming that _hfe is sufficiently large.
2 is a current obtained by adding the collector current Ic31 of the first transistor 31 and the collector current Ic32 of the second transistor 32, and is expressed by (Equation 20).

[0076]

Ic42 = Ic31 + Ic32 Further, the sum of the base-emitter voltage Vbe of the first transistor 31 and the base-emitter voltages of the transistors 42 to 4 (n-1) to the transistor 4n is the terminal voltage. It becomes equal to V61 and is expressed by (Equation 21).

[0077]

(Equation 21)

On the other hand, the base-emitter voltage Vbe of the second transistor 32 and the transistors 42-4 (n-1), 4n
The sum of the base-emitter voltages up to the terminal voltage V62
And is expressed by (Equation 22).

[0079]

(Equation 22)

From the equations (Equation 20) to (Equation 22) and the relational expressions (Equation 18) and (Equation 19) between the terminal voltages V61 and V62 of the N-th power circuit, the transistor 51
Is obtained as follows. First, based on (Equation 18) and (Equation 21), when V61, Is, and Vt are erased, they are expressed as (Equation 23).

[0081]

(Equation 23)

From (Equation 19) and (Equation 22), V62, Is,
When Vt is deleted, it is expressed as (Equation 24).

[0083]

(Equation 24)

If Ic31 and Ic32 are eliminated from the above (Equation 23), (Equation 24) and (Equation 20) to obtain Ic42, it is expressed as (Equation 25).

[0085]

(Equation 25)

Since the current Ic42 is input to the current mirror circuit 50 composed of the transistor 4n and the transistor 51, the collector current Ic51 of the transistor 51 is obtained.
Is equal to the current Ic42. Therefore, the output current Ic51 of this device is represented by (Equation 26).

[0087]

(Equation 26)

As described above, the first input current I601 and the first
, A second input current I602, a second N-th power circuit, a first transistor 31 having a base connected to the output of the first N-th power circuit, and a collector connected to the power supply voltage Vcc; A second transistor 32 having a base connected to the output of the N-th power circuit and a collector connected to the power supply voltage Vcc, and emitters of the first transistor 31 and the second transistor 32 connected to each other, and a transistor 42 connected to the emitter thereof 4 (n-1), a transistor 4n and a transistor 51
An output current Ic51 having a magnitude obtained by averaging the first input current I601 and the second input current I602 by the Nth power average can be obtained by the Nth power average circuit constituted by the current mirror circuit 50 composed of.

In the first embodiment, the number of inputs is two, but m inputs can be provided. FIG. 2 shows a configuration example when m inputs are provided. In the case where m inputs are provided as shown in FIG. 2, m N-th power circuits composed of n diode-connected transistors connected in series, a base connected to the output of the N-th power circuit, and a collector connected to the power supply voltage Vcc Are connected to the base and the collector of the transistor 42 which is an input of the N-th mean circuit.

Although the first embodiment uses a transistor, it may use another element such as a CMOS.

Next, FIG. 3 shows a configuration of an ALC device using the N-th mean circuit of the first embodiment in the second embodiment of the present invention. Here, a diagram showing the conventional example
Components corresponding to the components described in 13 are denoted by the same reference numerals, and the same applies to the following drawings. 3, 1 is an input terminal, 2 is an output terminal, 3 is a control terminal, 4 is a voltage-current converter, 5 is a variable gain amplifier, 6 is a voltage-current converter, 7 is a rectifier, and 8 is an external control signal. Current source, 10
Is a current-to-voltage converter, 10a is an amplifier, 10b is impedance, and 100 is a signal combiner for averaging Nth power. here,
The case where the signal synthesizer 100 is a mean square means will be described.

Now, when the voltage V1 is applied to the input terminal 1 of the variable gain amplifier 5, the voltage V1 is converted into the input current I1 by the voltage / current converter 4, and is expressed as (Expression 27).

[0093]

[Equation 27]

The converted input current I 1 is input as an input signal of the variable gain amplifier 5.

On the other hand, the input voltage V1 is also converted to a current I6 by the voltage-current converter 6, and further rectified by the rectifier 7 to become a rectified current | I6 | .

[0096]

[Equation 28]

The current I8 input to the control terminal 3 for controlling the gain of the ALC device is also input to the signal synthesizer 100 and synthesized with the rectified current | I6 |. This signal synthesizer 10
The control current I3 output from the control terminal 3 is the current I3 from the control terminal 3.
When a current value obtained by averaging the square of the rectified current | I6 | and the rectified current | I6 |

[0098]

(Equation 29)

The control current I 3 is input to the variable gain amplifier 5 as a control signal for the variable gain amplifier 5.

The variable gain amplifier 5 receives the input current I1
Functions as a divider that divides the current by the control current I3 from the signal synthesizer 100, which becomes a control signal. Therefore, when the input current I1 is input to the variable gain amplifier 5 and the control current I3 is input as the control signal, the variable gain The output current I2 of the amplifier 5 is as shown in (Equation 30).

[0101]

[Equation 30]

The output current I2 of the variable gain amplifier 5 is
The voltage is converted into a voltage V2 by the current-voltage converter 10, and the output voltage V2 is represented by (Expression 31).

[0103]

(Equation 31)

Here, Z10: conversion coefficient of the current-voltage converter 10, where the input voltage V1 is sufficiently small and the rectified current | I6 |
= | V1 | / Z6 is sufficiently smaller than the current I8 input to the control terminal 3 of the ALC device, that is, | V1 |
When / Z6≪I8, the denominator | V1 | / Z6 in (Equation 31) can be ignored, and the relationship between the input voltage V1 and the output voltage V2 is as shown in (Equation 32).

[0105]

(Equation 32)

As described above, when the input voltage V1 is small, the output voltage V2 becomes proportional to the magnitude of the input voltage V1, and the gain at that time is determined by Z10 / Z4 × I8.

On the other hand, when input voltage V1 is sufficiently large and rectified current | I6 | = | V1 | / Z6 is sufficiently larger than current I8 input to control terminal 3, ie, | V1 | /
When Z6≫I8, the denominator I8 in (Equation 31) can be ignored, and the relationship between the input voltage V1 and the output voltage V2 is as shown in (Equation 33).

[0108]

[Equation 33]

As described above, when the input voltage V1 increases, the magnitude of the output voltage V2 becomes independent of the magnitude of the input voltage V1, and the voltage-current converters 4, 6 and the current-voltage converter
It is determined by the ten transform coefficients Z4, Z6, and Z10.

FIG. 4 shows the relationship between the input voltage V1 and the output voltage V2 expressed by (Equation 32) and (Equation 33). The alternate long and short dash line in the drawing is an asymptote of the input / output characteristics of the constant gain region represented by (Equation 32) and the constant voltage output region represented by (Equation 33). The solid line indicates the characteristics of the conventional example in which the control signal synthesizing method is the mixer 9, the dotted line indicates the case where the control signal signal synthesizer 100 is of the mean square method, and the broken line indicates the control signal signal synthesizer 100 is the cube of power. This is the result when the average method is used.

As described above, the control signal signal synthesizer 100 is
By using the root mean square method or the root mean square method from the conventional mixing method, the output voltage characteristics of the ALC device can be approximated to the asymptote of the constant gain region and the asymptote of the constant voltage output region. The switching of the gain to the constant voltage output region can be made smooth and the switching can be made a clear change.

As described above, according to the ALC device described in the second embodiment, when the input voltage V1 is small, the output voltage V2 is in a constant gain region proportional to the magnitude of the input voltage V1, Is set by Z10 / (Z4 × I8). On the other hand, when the input voltage V1 increases, the magnitude of the output voltage V2 becomes a constant voltage output region that is independent of the magnitude of the input voltage V1, and the conversion coefficients of the voltage-current converters 4, 6 and the current-voltage converter 10 are changed. The voltage value is determined by Z4, Z6, and Z10. In addition, the signal synthesizer 100
By using the mean square method or the mean square method, an ALC device in which the switching of the output voltage characteristic from the constant gain region to the constant voltage output region is sharp can be configured.

In the second embodiment, two control currents are used for control. However, m control currents are controlled by a signal synthesizer.
The same effect can be obtained by inputting the signal to 100 and combining it to vary the gain of the variable gain amplifier 5.

Further, N in the N-th power averaging means used in the signal synthesizing means may be any value (real number), and the gain switching characteristic in that case varies depending on the N-th power averaging means. Although the variable gain amplifier 5 has a function of a current input current output divider, the variable gain amplifier 5 may function as a voltage input voltage output. In this case, the voltage-current converter and the current-voltage converter can be omitted.

The variable gain amplifier is not limited to the divider, but may be any as long as it has the same function.

Although the signal synthesizer 100 outputs the larger one of the input signals, the signal synthesizer 100 may output the smaller one. In this case, when the input signal is small, the characteristic of the output voltage is in the constant voltage output region, and when the input signal is large, the characteristic is switched to the constant gain region.

Next, FIG. 5 shows a configuration of a compressor device in the case where the control signal in the third embodiment is an output voltage and a current source. In FIG. 5, 1 is an input terminal, 2 is an output terminal, 3 is a control terminal, 4 is a voltage-to-current converter, 5 is a variable gain amplifier, 6 'is a voltage-to-current converter for converting an output voltage to a current, and 7' is a Rectifier, 8 is a current source serving as an external control signal, 10 is a current-voltage converter, 10a is an amplifier, 10b
Is an impedance, and 100 is a signal combiner for averaging Nth power. FIG. 6 shows the relationship between the input voltage V1 and the output voltage V2.

As shown in FIG. 6, when rectified current | I6 '| obtained from output voltage V2 is smaller than current source 8,
The output voltage V2 has a constant gain proportional to the input voltage V1 set by the current I8 of the current source 8. On the other hand, the output voltage V2 increases and the rectified current | I6 'obtained from the output voltage V2.
Is larger than the current I8, the current is controlled by the rectified current | I6 '| obtained from the output voltage V2, and the output voltage V2 is compressed by a factor of 1/2 in decibels. It is possible to configure a compressor device in which the change of the gain can be made smooth and a clear change can be made.

Next, FIG. 7 is a block diagram showing a configuration of a compressor device having an ALC function according to Embodiment 4 of the present invention. In FIG. 7, 1 is an input terminal, 2 is an output terminal, 4 is a voltage-current converter, 5 is a variable gain amplifier,
6 is a voltage-current converter for converting the input voltage V1, 6 'is a voltage-current converter for converting the output voltage V2, 7, 7' are rectifiers, and 100 is a signal combiner.

The configuration of the fourth embodiment is a compressor device in which the ALC function is added by simply adding a voltage-current converter and a rectifier to the conventional compressor device shown in FIG.

The variable gain amplifier 5 is configured to handle signal input and output by current, and the input is a virtual ground point. The voltage-current converter 4 converts the input voltage V1 applied to the input terminal 1 into a current and inputs the current to the variable gain amplifier 5, and the output current of the variable gain amplifier 5 is a current-voltage converter 10 comprising an amplifier 10a and an impedance 10b. To convert to voltage.

The rectifiers 7 and 7 'are configured to handle signal input / output by current, and the input is a virtual ground point. The voltage-current converter 6 converts an input voltage V1 applied to the input terminal 1 into a current and inputs the current to the rectifier 7. The voltage-current converter 6 'converts the output voltage V2 of the output terminal 2 into a current and inputs the current to the rectifier 7'. The signal combiner 100 combines the output signal current of the rectifier 7 and the output signal current of the rectifier 7 ′ and uses it as a control current for the variable gain amplifier 5.

Further, the variable gain amplifier 5 functions as a divider for dividing the output current from the voltage-current converter 4 by the output signal from the signal combiner 100. In this case, the signal combiner 100 The output signal current of the rectifier 7 and the output signal current of the rectifier 7 'are squared.

The operation of the fourth embodiment configured as described above will be described. Input terminal 1 of compressor device
, The voltage V1 is converted into the current I1 by the voltage-current converter 4, and is expressed as in (Expression 34).

[0125]

(Equation 34)

This converted current I 1 is input as an input signal of variable gain amplifier 5.

On the other hand, the input voltage V1 is also converted into a current I6 by the voltage-current converter 6, and further rectified by the rectifier 7 to become a rectified current | I6 | .

[0128]

(Equation 35)

The output voltage V2 is applied to the voltage / current converter 6 '.
Is converted to a current I6 ', and further rectified by a rectifier 7' to become a rectified current | I6 '|

[0130]

[Equation 36]

Output current of rectifier 7 and rectifier 7 '| I6 |
And | I6 '| are input to the signal synthesizer 100, output as a control current I3 by averaging the squares, and are expressed by (Expression 37).

[0132]

(37)

The control current I3 is input to the variable gain amplifier 5 as a control signal for the variable gain amplifier 5.

The variable gain amplifier 5 receives the input current I
1 is a control current I3 from the signal synthesizer 100 to be a control signal.
When the input current I1 is input to the variable gain amplifier 5 and the control current I3 is input as the control signal, the output current I2 of the variable gain amplifier 5 becomes as shown in (Equation 38). Become.

[0135]

(38)

The output current I2 of the variable gain amplifier 5 is
The output voltage V2 is converted by the current-voltage converter 10 into an output voltage V2, and the output voltage V2 is represented by (Expression 39).

[0137]

[Equation 39]

Here, Z10: conversion coefficient of the current-voltage converter 10, where the input voltage V1 is small and the rectified current | I6 '|
| V2 | / Z6 'is the rectified current | I6 | = | V1 | /
When it is sufficiently larger than Z6, that is, | V1 | / Z6≪ |
In the case of V2 | / Z6 ′, (| V1 | / Z
6) ² can be ignored and the input voltage V1 and the output voltage V
The relationship of 2 is as shown in (Equation 40).

[0139]

(Equation 40)

As described above, when the input voltage V1 is small,
That is, when | V1 | / Z6≪ | V2 | / Z6 ′, the output voltage V2 is proportional to the half power of the input voltage V1, and the input signal level width is compressed by a factor of 1/2 in decibels. And the same characteristics as those of the conventional compressor device can be obtained.

In the control current, the rectified current | I6 '
| = | V2 | / Z6 'is a rectified current | I6 | = | V1
| / Z6, that is, | V1 | / Z6
In the case of ≫ | V2 | / Z6 ′, the denominator (| V2 |
/ Z6 ') ² can be ignored, and the relationship between the input voltage V1 and the output voltage V2 is as shown in (Expression 41).

[0142]

[Equation 41]

As described above, when the input voltage V1 increases, the magnitude of the output voltage V2 becomes independent of the magnitude of the input voltage V1, and the voltage-current converters 4, 6 and the current-voltage converter
It is determined by the ten transform coefficients Z4, Z6, and Z10.

FIG. 8 shows the relationship between the input voltage V1 and the output voltage V2 in the configuration of the fourth embodiment shown in FIG. 7 obtained from (Equation 40) and (Equation 41).

As described above, according to the fourth embodiment,
A voltage-current converter 6 and a rectifier 7 are added to a conventional compressor device.
Only when the input voltage V1 is small, the output voltage V2 becomes proportional to the half power of the input voltage V1, and the input signal level width is compressed by a factor of 1/2 in decibels. The same characteristics as the device can be obtained. On the other hand, when the input voltage V1 increases, the output voltage V2
Is a constant voltage output region that is independent of the magnitude of the input voltage V1. The voltage value is determined by the conversion coefficients Z4, Z6, and Z10 of the voltage-current converters 4, 6 and the current-voltage converter 10. Become. Further, by using the N-mean-square method for the signal synthesizer 100, it is possible to configure a compressor device capable of smoothly and clearly changing the output voltage characteristic from the compressor region to the constant voltage region. .

Although the variable gain amplifier 5 has a function of a current input current output divider, the variable gain amplifier 5 may function as a voltage input voltage output. In this case, the voltage-current converter and the current-voltage converter can be omitted.

Further, the variable gain amplifier 5 need not be a divider as long as it has a similar function. The input / output characteristics in that case are determined by the input / output characteristics of the variable gain amplifier.

Although the signal combiner 100 outputs the larger one of the input signals, it may output the smaller one. In this case, the characteristics of the output voltage are such that when the input signal is small, the region is a constant voltage output region, and when the input signal is large, the region is switched to the compressor region.

Although the N-th power averaging means is used for synthesizing the control current, the same effect can be obtained by using the conventional mixing means, but in this case, the gain switching characteristic does not change clearly.

FIG. 9 shows a configuration of a compressor device according to the fifth embodiment of the present invention in which three control signals are input. As shown in FIG. 9, a control signal is synthesized by controlling three signals of the input voltage V1, the output voltage V2, and the current source 8 by using N-mean averaging means, and the control signal is combined with the input voltage V1 and the output voltage V2. FIG. 10 shows the relationship.

When the rectified currents | I6 | and | I6 '| obtained from the input signal V1 and the output signal V2 are smaller than the current I8 of the current source 8 input from the control terminal 3, the output voltage V
2 has a gain characteristic determined by the current I8 input from the control terminal 3, and has a constant gain proportional to the input voltage V1.

When output voltage V2 increases and rectified current | I6 '| obtained from output voltage V2 increases,
The output signal V2 has the characteristics of a compressor that compresses the amplitude level width by half in decibels.

When the input voltage V1 increases and the rectified current | I6 | obtained from the input voltage V1 increases, the output signal V2 has the characteristics of an ALC that outputs a constant voltage regardless of the magnitude of the input signal V1. Thus, it is possible to configure a compressor device in which the switching of the gain can be smoothly and clearly changed.

FIG. 11 shows a configuration of an expander device in which the variable gain amplifying means according to the sixth embodiment of the present invention is a multiplier. FIG. 12 shows the relationship between the input voltage V1 and the output voltage V2 that provide a control signal to the expander device. That is, a rectified current | I6 | obtained from the input voltage V1 is supplied from the control terminal 3 to the current source 8
Is smaller than the current I8 of the control terminal 3,
The gain characteristic is determined by the current I8 input from the input terminal and becomes a constant gain proportional to the input voltage V1. In addition, the input voltage V1 increases and the rectified current | obtained from the input voltage V1 |
When I6 | becomes large, the output voltage V2 can obtain the characteristic of an expander that is doubled by a decibel of the input voltage V1, and the gain can be switched smoothly and clearly. Can be configured.

The variable gain amplifier functions as a multiplier, and a control signal is obtained from the current source 8 and the output voltage V2, a configuration is obtained from the input voltage V1 and the output voltage V2, and a control signal is obtained from the input voltage V1 and the output voltage. Even with a configuration obtained from the three control signals of the voltage V2 and the current source 8, it is possible to configure an expander device in which the switching of the gain is smooth and can be made a clear change.

Further, N in the N-th power averaging means of the signal combining means may be any value (real number). In this case, the gain switching characteristic is changed by the signal combiner 100.

[0157]

As described above, according to the N-th power averager of the present invention, the first N-th power means constituted by n transistors connected in series and the n-th transistors connected in series are provided. A second N-th power means, a transistor group composed of (n-2) transistors connected in series, a first transistor having a base connected to the output of the first N-th power means and a collector connected to the power supply voltage, A second transistor having a base connected to the output of the second N-th power means and a collector connected to the power supply voltage, and an emitter connected to an emitter of a transistor group to which the first and second transistors are connected to each other. The output current having a magnitude obtained by averaging Nth power of the first input current and the second input current can be obtained by the Nth power averaging means constituted by the current mirror circuit.

Further, according to the ALC device thus configured, when the input current inputted to the signal combiner is compared with the current source, when the input current is small, the output voltage is in a constant gain region proportional to the magnitude of the input voltage. And is set by the current source. on the other hand,
When the input current is large, the output voltage becomes a constant voltage output region that outputs a constant voltage regardless of the magnitude of the input voltage. The switching of the gain of the output voltage characteristic from the constant gain region to the constant voltage output region can be clearly changed by the control current obtained by combining the input current of the input signal and the input of the current source by the N-th power mean.

The rectified current obtained from the output current input to the signal synthesizer is compared with the current source. When the rectified current is small, the constant gain region is set by the current source. To compress the signal level width to 1/2 in decibels so that the output voltage is proportional to the 1/2 power of the input voltage. By the control current obtained by combining the output current and the input of the current source by the N-th power mean, the switching of the gain can be made smooth and clear.

When the input current and the output current input to the signal combiner are compared with each other, when the input current is small, the signal level width is set to 1 dB so that the output voltage is proportional to the square of the input voltage. / 2 compression. Further, it is possible to configure a compressor device having an ALC function that outputs a constant output voltage irrespective of the input voltage when the input current increases, and furthermore, a control current obtained by combining the input current and the output current by N-th power average. Thus, the switching of the gain can be clearly changed.

The signal input to the signal combining means is N
The use of the averaging means has an effect that the switching of the gain from the constant gain controlled by the control signal to the compressor operation, the expander operation or the ALC operation can be made smooth and clear.

[Brief description of the drawings]

FIG. 1 shows a specific configuration diagram of an N-mean-square apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating a configuration example in a case where m inputs of the N-th power average device according to the first embodiment are provided.

FIG. 3 is a diagram illustrating a configuration of an ALC device using an N-th power average circuit according to the first embodiment in the second embodiment of the present invention;

FIG. 4 is a diagram showing a relationship between an input voltage V1 and an output voltage V2 of the ALC device according to the second embodiment.

FIG. 5 is a diagram illustrating a configuration of a compressor device when a control signal is an output voltage and a current source according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a relationship between an input voltage V1 and an output voltage V2 of the compressor device according to the third embodiment.

FIG. 7 is a block diagram illustrating a configuration of a compressor device to which an ALC function is added according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between an input voltage V1 and an output voltage V2 of a compressor device having an ALC function according to a fourth embodiment.

FIG. 9 is a block diagram illustrating a configuration of a compressor device according to a fifth embodiment of the present invention in which three control signals are input.

FIG. 10 is a diagram showing a relationship between an input voltage V1 and an output voltage V2 of a compressor device according to a fifth embodiment.

FIG. 11 is a block diagram showing a configuration of an expander device according to a sixth embodiment of the present invention, in which a variable gain amplifying means is used as a multiplier.

FIG. 12 is a diagram illustrating a relationship between an input voltage V1 and an output voltage V2 of the expander device according to the sixth embodiment.

FIG. 13 is a block diagram showing a case where a conventional Philips NE / SA572 is configured as an ALC device.

FIG. 14 is a diagram showing a relationship between an input voltage V1 and an output voltage V2 of a conventional ALC device.

FIG. 15 is a block diagram showing a case where a conventional Philips NE / SA572 is configured as a compressor device.

FIG. 16 is a block diagram showing a case where the conventional Philips NE / SA572 is configured as an expander device.

[Explanation of symbols]

1: input terminal, 2: output terminal, 3: control terminal,
4, 6, 6 '... voltage-current converter, 5 ... variable gain amplifier, 7, 7' ... rectifier, 8 ... current source, 9 ... mixer, 10 ... current-voltage converter, 10a ... amplifier, 10b ... impedance 11-1n, 21-2n, 4n, 51, m1-mn
... transistors, 31, 32, 3m ... first, second, and m-th transistors, 42-4 (n-1) ... transistor groups,
50: current mirror circuit, 52: current output terminal, 61,
62, 6m: current input terminal, 100: signal synthesizer, 601, 6
02, 60m: The first, second, and m-th current sources.

Claims (7)

[Claims] 1. A first N-th power means for raising a first signal to the Nth power, a second N-th power means for raising the second signal to the Nth power, and a first Nth power means.
An N-th power averaging device, comprising: N-th power averaging means for mixing a raised signal and a second N-th power signal and performing an N-th root. 2. A first N-th means in which n number of diode-connected transistors for raising the first signal current to the Nth power are connected in series, and n number of diode-connected transistors for raising the second signal current to the Nth power are provided. Second N-th means connected in series;
(n-2) transistors connected in series and the first
A first transistor having a base connected to the output of the N-th power means, a collector connected to the power supply voltage, and an emitter connected to the input of the transistor group; and a base connected to the output of the second N-th power means. A second transistor having a collector connected to the power supply voltage, an emitter connected to the input of the transistor group, and a current mirror circuit having a signal from the emitter of the transistor group as an input and an output as an output of the device. An N-mean-squaring apparatus comprising: N-mean-squaring. 3. m-th power means in which n diode-connected transistors for raising a signal current to the Nth power are connected in series;
(n-2) transistors connected in series, and m bases connected to the output of each of the N-th power means, a collector connected to a power supply voltage, and an emitter connected to an input of the transistor group An N-th power averaging device, comprising: a transistor; and a current mirror circuit which receives a signal from an emitter of the transistor group as an input and outputs the output of the device, and performs N-th power averaging. 4. A variable gain amplifying means for varying a gain of an input signal by a control signal, a rectifying means for rectifying the input signal, and an N-th power average of an output signal of the rectifying means and an external control signal. And a signal synthesizing means for outputting the control signal. 5. A variable gain amplifying means for varying a gain of an input signal by a control signal, a rectifying means for rectifying an output signal of the variable gain amplifying means, and an output signal of the rectifying means and an external control signal. An amplitude compression / expansion apparatus, comprising: a signal synthesizing unit that synthesizes by N-mean averaging and outputs the control signal. 6. A variable gain amplifying means for varying a gain of an input signal by a control signal, a first rectifying means for rectifying the input signal, and a rectifying means for rectifying an output signal of the variable gain amplifying means. 2 rectifying means, and a signal synthesizing means for synthesizing the output signal of the first rectifying means and the output signal of the second rectifying means by N-th power averaging and outputting the control signal. The amplitude compression and expansion device. 7. A variable gain amplifying means for varying a gain of an input signal by a control signal, a first rectifying means for rectifying the input signal, and a rectifying means for rectifying an output signal of the variable gain amplifying means. 2 rectifying means, and a signal combining means for combining the output signal of the first rectifying means, the output signal of the second rectifying means, and the external control signal by N-th power averaging and outputting the control signal. An amplitude compression / expansion device, comprising: