CA1208711A - Electronic gain-control arrangement - Google Patents
Electronic gain-control arrangementInfo
- Publication number
- CA1208711A CA1208711A CA000484622A CA484622A CA1208711A CA 1208711 A CA1208711 A CA 1208711A CA 000484622 A CA000484622 A CA 000484622A CA 484622 A CA484622 A CA 484622A CA 1208711 A CA1208711 A CA 1208711A
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- arrangement
- current
- transistors
- current distribution
- voltage
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Abstract
ABSTRACT:
A gain control arrangement comprises a first cur-rent distribution circuit (101) having two transistors whose emitters are connected to a first current source (103) and a second current distribution circuit (102) having two transistors whose emitters are connected to a second current source (104). The bases of the transistors of the first (101) and second (102) current distribution are intercon-nected and a control voltage (ust) is applied between the bases of each current distribution circuit. The collectors of two transistors of the first (101) and second (102) cur-rent distribution circuits which vary in the same sense by the control voltage (ust) are connected to the emitters of two transistors (105,106), between which a first impedance element (107) is arranged. The input signal (ui) of the arrangement is applied between the bases of these transis-tors (105,106), whose collectors are connected to a first (108) and a second (109) resistor. The voltage across these resistors (108,109) is amplified by a first opera-tional amplifier (110), whose output voltage is applied to a converter circuit (120), which converts said voltage into two opposite-phase output currents, which are applied to the interconnected emitters of the first (101) and second (102) current distribution circuits. The collectors of the other two transistors of the first (101) and second (102) current distribution circuits are connected to the emitters of two further transistors (112,113) between which a second impedance element (111) is arranged. The collectors of these transistors (112,113) are connected to a third (114) and a fourth (115) resistor respectively. The voltage across these resistors (114,115) is amplified by a second operational amplifier (116) whose output voltage (uo) is applied between the bases of the two further transistors (112,113). This output voltage (uo) also forms the output voltage of the arrangement. This output voltage (uo) is related to the control voltage (ust) in accordance with an exponential function over a wide range of control voltages.
A gain control arrangement comprises a first cur-rent distribution circuit (101) having two transistors whose emitters are connected to a first current source (103) and a second current distribution circuit (102) having two transistors whose emitters are connected to a second current source (104). The bases of the transistors of the first (101) and second (102) current distribution are intercon-nected and a control voltage (ust) is applied between the bases of each current distribution circuit. The collectors of two transistors of the first (101) and second (102) cur-rent distribution circuits which vary in the same sense by the control voltage (ust) are connected to the emitters of two transistors (105,106), between which a first impedance element (107) is arranged. The input signal (ui) of the arrangement is applied between the bases of these transis-tors (105,106), whose collectors are connected to a first (108) and a second (109) resistor. The voltage across these resistors (108,109) is amplified by a first opera-tional amplifier (110), whose output voltage is applied to a converter circuit (120), which converts said voltage into two opposite-phase output currents, which are applied to the interconnected emitters of the first (101) and second (102) current distribution circuits. The collectors of the other two transistors of the first (101) and second (102) current distribution circuits are connected to the emitters of two further transistors (112,113) between which a second impedance element (111) is arranged. The collectors of these transistors (112,113) are connected to a third (114) and a fourth (115) resistor respectively. The voltage across these resistors (114,115) is amplified by a second operational amplifier (116) whose output voltage (uo) is applied between the bases of the two further transistors (112,113). This output voltage (uo) also forms the output voltage of the arrangement. This output voltage (uo) is related to the control voltage (ust) in accordance with an exponential function over a wide range of control voltages.
Description
PHD 82.012 Div.
This application is a division of application Serial No. 420,809.
'rhe invention relates to an electronic gain con-trol arrangement, i.e. to a circuit arrangement whose gain can be varied by means of a control voltage. Such a cir-cuit arrangement is known from DE-PS 24 04 331 which was published on February 9, 1978. The arrangement described therein comprises two converter circuits whose high-impedance outputs are each connected to the inputs of a current distribution circuit. Two outputs of the current distribution circuits, whose output currents can be con-trolled by the control voltage on the control input of thecurrent distribution circuit, have a common resistor through which the output currents flow. The voltage across this resistor is applied to the inputs of the two converter circuits via an amplifier so as to obtain negative feed-back, the input signal of the circuit arrangement alsobeing applied to one converter circuit~
In many cases the control characteristic of such a circuit arrangement, should be such that the amplitude of the output voltage is related to the control voltage e~actly in accordance with an e-function, which is referred to hereinafter as "dB-linear". The known circuit arrange-ment, however, has a dB linear control characteristic over a very small amplification range and moreover produces com-paratively strong even harmonics on its output. The last-mentioned disadvantage is mitigated in the circuit arrangement in accordance with German Patent Applicatlon P 30 24 142.0 which was published on January 21, 1982~
This arrangement in addition comprises two further current distribution circuits and two further converter circuits, the phase of the signal applied to the additional current distribution circuits via the additional converter circuits ' being opposed to that of the signal applied to the two other current distribution circuits. The output voltage is subtracted. However, this circuit arrangement also has a dB-linear control characteristic over a comparatively small range.
PHD 82.012 Div. 2 From US-PS 3,714,462 an electronic gain control arrangement is known which comprises two pnp and two npn-transistors and which has a ds-linear control characteris-tic over a comparatively large range if the characteristics of these transistors correspond to each other. However, since this requires the use of transistors of opposite con-ductivity types with matching characteristics, this circuit arrangement cannot readily be constructed in integrated circuit technology.
It is the object of the present invention to pro-vide a circuit arrangement having a dB-linear control char-acteristic over a comparatively large range and whose pro-perties are determined by transistors bf one conductivity type only.
In accordance with the invention an electronic gain control arrangement comprising two current distribu-tion circuits each having two outputs r the output current ratio being controllable as an exponential function of the control voltage on their control inputs, is characteri7ed in that there is provided a current control circuit which supplies signal currents which are equal but in phase opposition to the inputs of the current distribution cir-cuits and which controls their amplitudes depending on the input signal of the arrangement in such a way that the out-put currents on each one of the two outputs of the twocurrent distribution circuits are proportional to the input signal and independent of the control voltage, and the out-put signal of the arrangement is derived from at least one o~ the output currents of the two other outputs of the cur rent distribution circuits, which output currents are con-trolled in the same sense by the control voltage.
The circuit of the invention employs a current distribution circuit in which the ratio of the ou-tput cur-rents is an exponential function of the control voltage on the control input of the current distribution circuit.
Current distribution circuits of this type are known. In the simplest foxm they comprise two emitter-coupled bipolar transistors. The interconnected emitters form the signal il'7~
PHD 82.012 Div. 3 input of the current distribution circuit and the two col-lectors form the two outputs of the current distribution circuit. The control voltage is applied to the base elec-trodes of the two transistors. In principle the dB-linear characteristic is determined only by the characteristics of these transistors of the same conductivity type which form the current distribution circuits.
With the circuit of the invention only the cur rent in each time one branch of the current distribution circuits remains independent of the control voltage, as a result of which the current in the other branch of the cur-rent distribution circuit increases exponentially so that the output signal of the arrangement can be derived from this current.
An advantage of the circuit arrangement is that in the case of a symmetrical design the arrangement pro duces substantially no even harmonics.
The invention will now be described in more detail, by way of e~ample, with reference to the drawing, in which Fig. 1 shows an embodiment of the circui.t in accordance with the invention.
The embodiment shown comprises current dis-tribu-tion circuits 101 and 102, which each comprise two bipolar transistors of the same conductivity type, suitably of the npn-type, whose emitters are interconnected. The base of one transistor of a current distribution circuit is con-nected to the base of a transistor of the other current distribution circuit. A control voltage ust acts between the bases of the npn transistors forming each current dis-tribution circuit. As is known, the current applied to theemitters of such a transistor pair is distributed by the control voltage ust in such a way that the quotient of the collector currents is an exponential function of the con-trol voltage ust. The inputs of the current distribution circuits 101 and 102 respectively, i.e. the emitters o~ the npn transistors constituting the current distribution cir-cuits, are connected to a supply voltage terminal carrying a negative potential -U via a d.c source, 103 and 104 res-PHD 82.012 Div. 4 pectively. The collectors of two transistors of the cur-rent distribution circuits 101 and 102 whose bases are interconnected, i.e. those outputs of the current distri-bution circuits whose output-current amplitudes are varied in the same sense by the control voltage ust~ are connected to the emitters of two transistors 105 and 106, between which a two-terminal network 107 is arranged. The input signal ui is applied between the base electrodes of the transistors 105 and 106 and their collectors are connected to a supply voltage terminal carrying a positive potential +U via resistor 108 and 109. However, instead oE the individual transistors 105 and 106 any other circuit arrangement may be chosen having a low-impedance follower output and a further, high-impedance output, for example a Darlington arrangement, whilst the outputs of the current distribution circuits 101, 102 may be connected to the emitters of the output transistors of the Darlington arrangement or alternatively to the emitters of the pre-ceding transistors~
The voltage across the resistors 108 and 109, which suitably have the same values, is amplified by an operational amplifier 110 and applied to the input of a converter circuit 120, which converts said voltage into signal currents of equal amplitude but opposite phase r which are proportional to the output voltage of the ampli-fier 110, which signal currents are applied to the inputs of the current distribution circuits 101 and 102 respec-tively with such a phase that negative feedback is obtained.
It can be demonstrated that in this circuit arrangement the signal voltage on each of the two inputs of the operational amplifier 110 becomes substantially zero or that the collector signal currents are negligible relative to the current through the two-terminal network 107, if the product of the resistance value of one of the resistors 108 and 109, the gain of the operational amplifier 110 and the slope of the converter circuit 120 is great in comparison with the expression l+eC. Here e is the base of the nat-ural logarithm, c is a value which corresponds to the quo-7~
PHD ~2.012 Div. 5 tient of the control voltage ust and the thermal voltage(Ut ~26 mV at 300 K) or the logarithm of the quotient of the output currents of a current distribution circuit~
However, this means that the currents on the outputs of the current distribution circuit 101 and 102, which are con-nected to the transistors 105 and 106, have the same values and correspond to the current through the two-terminal net-work 107, which current is given by the relationship ui/Zl, where Zl is the impedance of the two terminal networ~ 107 -regardless of the control voltage ust~
Thus r the two current distribution circuits 101and 102 are arranged in a control loop or negative feedback loop which ensures that the signal currents on the outputs connected to the transistor 105 and 106 respectively become proportional to the input voltage ui~ namely independently o~ the control voltage ust. This is because the high gain in the negative feedback loop or feedback loop ensures that the currents through the resistors 108 and 109 are neglig-ible relative to the current through the resistor 107. In the ease of a deviation the alternating currents supplied : by the current converter 120 change in sueh a way that the signal eurrent or the signal-voltage drop across the resis-tors 108 and 109 respeetively is again negligible.
Since, as is known, the ratio of the currents on the two outputs of such a current circuit, is an exponen-tial function of the control voltage, the currents on those outputs of the current distribution circuits 101 and 102 which are not connectea to the transistors 105 and 106 are : a factor e c smaller or greater than the current through the resistor 107~ c having a positive or a negative value depending on the polarity of the control voltage ust.
Therefore, the signal voltage drop produced across a resis-tor connected to one of these outputs divided by the input signal voltage ui would already be an exponential function of the control uSt, but such an output voltage would be available across a comparatively high impedance and would not be exempt of second harmonics. However, i~ the output currents or signals which are proportional thereto are sub-1~8~
PHD 82.012 Div. 6 tracted from each other, a compensation for the even har-monics is obtained because said harmonics in the output current are in phase whilst the actual signal components in the output currents are in phase opposition.
For this purpose those outputs of the current dis-tribution circuits 101 and 102 which are not connected to the transistors 105 and 106 are interconnected vla a second impedance 111. The voltage across this impedance can be regarded as the output voltage. ~owever, in that case the circuit shows a comparatively high output resistance.
Therefore, the two-terminal network 111 is arranged between the emitter connections of two npn transistors 112 and 113, whose collectors are connected to the positive supply volt-age terminal ~U vla resistors 114 and 115 of equal value.
The base of one of the two transistors (113) is connected to a reference potential, for example earth, the base of the other transistor (112) to the output of an operational amplifier 116, which amplifies the difference between the voltage drops across the resistors 114 and 115, in such a way that a negative feedback is obtained. The output volt-age uO of this operational amplifier corresponds to the voltage across ~he two-terminal network 111, but is now available on a low impedance voltage terminal and is asym-; metrical relative to earth.
During the half-cycle of the input signal indi-cated by the current arrows the transistor 105 and the transistors of the current distribution circuit 101 are more conductive than the transistor 106 and the transistors of the current distribution circuit 102 respectively. Dur-ing the opposite half-cycle the situation is reversed.
This results in a push-pull operation, which as ~nown does not give rise to even harmonics.
If the first and the second impedances 107, 111 respectively are real or if their phase angles ~ary in the same way as a function of the frequency, the circuit arrangement may be used for electronic gain control, in order to vary the gain uniformly over a wider frequency band, or it may be used as a volume control circuit in an PHD 82.012 Div. 7 audio amplifier. The gain can then be determined by a suitable choice of the impedances Zl and Z2 of resistors 107 and lll respectively.
Such a circuit arrangement is also suitable for automatic gain control in RF receivers.
However, if one of the two impedances is fre-quency-dependent in a different manner the frequency re-sponse may be influenced depending on the control voltage ust or a frequency-dependent gain control is possible, which permits its use as a filter with voltage controlled cut-off frequency or as tone control in audio amplifiers.
If the first two-terminal network 107 is a resistor and the second two-terminal network 111 a capacitor or a cap-acitive impedance r an integrator with electronically con-trollable time constant is obtained, which may for examplebe used in control technology.
In that case the phase of the oukput signal may be shifted through 180~ by interchanging the input connections.
This application is a division of application Serial No. 420,809.
'rhe invention relates to an electronic gain con-trol arrangement, i.e. to a circuit arrangement whose gain can be varied by means of a control voltage. Such a cir-cuit arrangement is known from DE-PS 24 04 331 which was published on February 9, 1978. The arrangement described therein comprises two converter circuits whose high-impedance outputs are each connected to the inputs of a current distribution circuit. Two outputs of the current distribution circuits, whose output currents can be con-trolled by the control voltage on the control input of thecurrent distribution circuit, have a common resistor through which the output currents flow. The voltage across this resistor is applied to the inputs of the two converter circuits via an amplifier so as to obtain negative feed-back, the input signal of the circuit arrangement alsobeing applied to one converter circuit~
In many cases the control characteristic of such a circuit arrangement, should be such that the amplitude of the output voltage is related to the control voltage e~actly in accordance with an e-function, which is referred to hereinafter as "dB-linear". The known circuit arrange-ment, however, has a dB linear control characteristic over a very small amplification range and moreover produces com-paratively strong even harmonics on its output. The last-mentioned disadvantage is mitigated in the circuit arrangement in accordance with German Patent Applicatlon P 30 24 142.0 which was published on January 21, 1982~
This arrangement in addition comprises two further current distribution circuits and two further converter circuits, the phase of the signal applied to the additional current distribution circuits via the additional converter circuits ' being opposed to that of the signal applied to the two other current distribution circuits. The output voltage is subtracted. However, this circuit arrangement also has a dB-linear control characteristic over a comparatively small range.
PHD 82.012 Div. 2 From US-PS 3,714,462 an electronic gain control arrangement is known which comprises two pnp and two npn-transistors and which has a ds-linear control characteris-tic over a comparatively large range if the characteristics of these transistors correspond to each other. However, since this requires the use of transistors of opposite con-ductivity types with matching characteristics, this circuit arrangement cannot readily be constructed in integrated circuit technology.
It is the object of the present invention to pro-vide a circuit arrangement having a dB-linear control char-acteristic over a comparatively large range and whose pro-perties are determined by transistors bf one conductivity type only.
In accordance with the invention an electronic gain control arrangement comprising two current distribu-tion circuits each having two outputs r the output current ratio being controllable as an exponential function of the control voltage on their control inputs, is characteri7ed in that there is provided a current control circuit which supplies signal currents which are equal but in phase opposition to the inputs of the current distribution cir-cuits and which controls their amplitudes depending on the input signal of the arrangement in such a way that the out-put currents on each one of the two outputs of the twocurrent distribution circuits are proportional to the input signal and independent of the control voltage, and the out-put signal of the arrangement is derived from at least one o~ the output currents of the two other outputs of the cur rent distribution circuits, which output currents are con-trolled in the same sense by the control voltage.
The circuit of the invention employs a current distribution circuit in which the ratio of the ou-tput cur-rents is an exponential function of the control voltage on the control input of the current distribution circuit.
Current distribution circuits of this type are known. In the simplest foxm they comprise two emitter-coupled bipolar transistors. The interconnected emitters form the signal il'7~
PHD 82.012 Div. 3 input of the current distribution circuit and the two col-lectors form the two outputs of the current distribution circuit. The control voltage is applied to the base elec-trodes of the two transistors. In principle the dB-linear characteristic is determined only by the characteristics of these transistors of the same conductivity type which form the current distribution circuits.
With the circuit of the invention only the cur rent in each time one branch of the current distribution circuits remains independent of the control voltage, as a result of which the current in the other branch of the cur-rent distribution circuit increases exponentially so that the output signal of the arrangement can be derived from this current.
An advantage of the circuit arrangement is that in the case of a symmetrical design the arrangement pro duces substantially no even harmonics.
The invention will now be described in more detail, by way of e~ample, with reference to the drawing, in which Fig. 1 shows an embodiment of the circui.t in accordance with the invention.
The embodiment shown comprises current dis-tribu-tion circuits 101 and 102, which each comprise two bipolar transistors of the same conductivity type, suitably of the npn-type, whose emitters are interconnected. The base of one transistor of a current distribution circuit is con-nected to the base of a transistor of the other current distribution circuit. A control voltage ust acts between the bases of the npn transistors forming each current dis-tribution circuit. As is known, the current applied to theemitters of such a transistor pair is distributed by the control voltage ust in such a way that the quotient of the collector currents is an exponential function of the con-trol voltage ust. The inputs of the current distribution circuits 101 and 102 respectively, i.e. the emitters o~ the npn transistors constituting the current distribution cir-cuits, are connected to a supply voltage terminal carrying a negative potential -U via a d.c source, 103 and 104 res-PHD 82.012 Div. 4 pectively. The collectors of two transistors of the cur-rent distribution circuits 101 and 102 whose bases are interconnected, i.e. those outputs of the current distri-bution circuits whose output-current amplitudes are varied in the same sense by the control voltage ust~ are connected to the emitters of two transistors 105 and 106, between which a two-terminal network 107 is arranged. The input signal ui is applied between the base electrodes of the transistors 105 and 106 and their collectors are connected to a supply voltage terminal carrying a positive potential +U via resistor 108 and 109. However, instead oE the individual transistors 105 and 106 any other circuit arrangement may be chosen having a low-impedance follower output and a further, high-impedance output, for example a Darlington arrangement, whilst the outputs of the current distribution circuits 101, 102 may be connected to the emitters of the output transistors of the Darlington arrangement or alternatively to the emitters of the pre-ceding transistors~
The voltage across the resistors 108 and 109, which suitably have the same values, is amplified by an operational amplifier 110 and applied to the input of a converter circuit 120, which converts said voltage into signal currents of equal amplitude but opposite phase r which are proportional to the output voltage of the ampli-fier 110, which signal currents are applied to the inputs of the current distribution circuits 101 and 102 respec-tively with such a phase that negative feedback is obtained.
It can be demonstrated that in this circuit arrangement the signal voltage on each of the two inputs of the operational amplifier 110 becomes substantially zero or that the collector signal currents are negligible relative to the current through the two-terminal network 107, if the product of the resistance value of one of the resistors 108 and 109, the gain of the operational amplifier 110 and the slope of the converter circuit 120 is great in comparison with the expression l+eC. Here e is the base of the nat-ural logarithm, c is a value which corresponds to the quo-7~
PHD ~2.012 Div. 5 tient of the control voltage ust and the thermal voltage(Ut ~26 mV at 300 K) or the logarithm of the quotient of the output currents of a current distribution circuit~
However, this means that the currents on the outputs of the current distribution circuit 101 and 102, which are con-nected to the transistors 105 and 106, have the same values and correspond to the current through the two-terminal net-work 107, which current is given by the relationship ui/Zl, where Zl is the impedance of the two terminal networ~ 107 -regardless of the control voltage ust~
Thus r the two current distribution circuits 101and 102 are arranged in a control loop or negative feedback loop which ensures that the signal currents on the outputs connected to the transistor 105 and 106 respectively become proportional to the input voltage ui~ namely independently o~ the control voltage ust. This is because the high gain in the negative feedback loop or feedback loop ensures that the currents through the resistors 108 and 109 are neglig-ible relative to the current through the resistor 107. In the ease of a deviation the alternating currents supplied : by the current converter 120 change in sueh a way that the signal eurrent or the signal-voltage drop across the resis-tors 108 and 109 respeetively is again negligible.
Since, as is known, the ratio of the currents on the two outputs of such a current circuit, is an exponen-tial function of the control voltage, the currents on those outputs of the current distribution circuits 101 and 102 which are not connectea to the transistors 105 and 106 are : a factor e c smaller or greater than the current through the resistor 107~ c having a positive or a negative value depending on the polarity of the control voltage ust.
Therefore, the signal voltage drop produced across a resis-tor connected to one of these outputs divided by the input signal voltage ui would already be an exponential function of the control uSt, but such an output voltage would be available across a comparatively high impedance and would not be exempt of second harmonics. However, i~ the output currents or signals which are proportional thereto are sub-1~8~
PHD 82.012 Div. 6 tracted from each other, a compensation for the even har-monics is obtained because said harmonics in the output current are in phase whilst the actual signal components in the output currents are in phase opposition.
For this purpose those outputs of the current dis-tribution circuits 101 and 102 which are not connected to the transistors 105 and 106 are interconnected vla a second impedance 111. The voltage across this impedance can be regarded as the output voltage. ~owever, in that case the circuit shows a comparatively high output resistance.
Therefore, the two-terminal network 111 is arranged between the emitter connections of two npn transistors 112 and 113, whose collectors are connected to the positive supply volt-age terminal ~U vla resistors 114 and 115 of equal value.
The base of one of the two transistors (113) is connected to a reference potential, for example earth, the base of the other transistor (112) to the output of an operational amplifier 116, which amplifies the difference between the voltage drops across the resistors 114 and 115, in such a way that a negative feedback is obtained. The output volt-age uO of this operational amplifier corresponds to the voltage across ~he two-terminal network 111, but is now available on a low impedance voltage terminal and is asym-; metrical relative to earth.
During the half-cycle of the input signal indi-cated by the current arrows the transistor 105 and the transistors of the current distribution circuit 101 are more conductive than the transistor 106 and the transistors of the current distribution circuit 102 respectively. Dur-ing the opposite half-cycle the situation is reversed.
This results in a push-pull operation, which as ~nown does not give rise to even harmonics.
If the first and the second impedances 107, 111 respectively are real or if their phase angles ~ary in the same way as a function of the frequency, the circuit arrangement may be used for electronic gain control, in order to vary the gain uniformly over a wider frequency band, or it may be used as a volume control circuit in an PHD 82.012 Div. 7 audio amplifier. The gain can then be determined by a suitable choice of the impedances Zl and Z2 of resistors 107 and lll respectively.
Such a circuit arrangement is also suitable for automatic gain control in RF receivers.
However, if one of the two impedances is fre-quency-dependent in a different manner the frequency re-sponse may be influenced depending on the control voltage ust or a frequency-dependent gain control is possible, which permits its use as a filter with voltage controlled cut-off frequency or as tone control in audio amplifiers.
If the first two-terminal network 107 is a resistor and the second two-terminal network 111 a capacitor or a cap-acitive impedance r an integrator with electronically con-trollable time constant is obtained, which may for examplebe used in control technology.
In that case the phase of the oukput signal may be shifted through 180~ by interchanging the input connections.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electronic gain control arrangement comprising two current distribution circuits each having two outputs, the output current ratio being controllable as an exponen-tial function of the control voltage on their control inputs, characterized in that there is provided a current control circuit, which supplies signal currents which are equal but in phase opposition to the inputs of the current distribution circuits and which controls their amplitude depending on the input signal of the arrangement in such a way that the output currents on each one of the two outputs of the two current distribution circuits are proportional to the input signal and independent of the control voltage, and the output signal of the arrangement is derived from at least one of the output currents of the two other outputs of the current distribution circuits, which output currents are controlled in the same sense by the control voltage.
2. An arrangement as claimed in Claim 1, character-ized in that, the current control circuit comprises an input converter, an amplifier connected to the output of said converter, and a current converter, which converts the output signal of the amplifier into two equal currents which are in phase opposition, and which are applied to the inputs of the current distribution circuits, and the input converter comprises two symmetrically arranged transistors between whose emitters a first two-terminal network, which is coupled to the outputs of the current distribution cir-cuits, is arranged, to whose bases the input signal of the arrangement is applied, and from whose collector currents the input signal of the amplifier is derived.
3. An arrangement as claimed in Claim 2, character-ized in that, the output signal is formed by the difference of the currents on those outputs of the current distribu-tion circuits which are not connected to the input con-verter.
4. An arrangement as claimed in Claim 3, character-ized in that, the output voltage is applied to a second two-terminal network which is arranged between those two outputs of the current distribution circuits which are not connected to the input converter.
5. An arrangement as claimed in Claim 4, character-ized in that the first and/or second two-terminal network comprise(s) a frequency-dependent impedance.
6. An arrangement as claimed in Claim 4, character-ized in that the second two-terminal network comprises a capacitive impedance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000484622A CA1208711A (en) | 1982-02-08 | 1985-06-20 | Electronic gain-control arrangement |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3204217.5 | 1982-02-08 | ||
| DE19823204217 DE3204217A1 (en) | 1982-02-08 | 1982-02-08 | CIRCUIT FOR THE ELECTRONIC AMPLIFIER POSITION |
| CA000420809A CA1203584A (en) | 1982-02-08 | 1983-02-03 | Electronic gain-control arrangement |
| CA000484622A CA1208711A (en) | 1982-02-08 | 1985-06-20 | Electronic gain-control arrangement |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000420809A Division CA1203584A (en) | 1982-02-08 | 1983-02-03 | Electronic gain-control arrangement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1208711A true CA1208711A (en) | 1986-07-29 |
Family
ID=25669929
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000484622A Expired CA1208711A (en) | 1982-02-08 | 1985-06-20 | Electronic gain-control arrangement |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1208711A (en) |
-
1985
- 1985-06-20 CA CA000484622A patent/CA1208711A/en not_active Expired
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