GB2442774A - Electronically adjustable gain slope controller circuit - Google Patents

Electronically adjustable gain slope controller circuit Download PDF

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Publication number
GB2442774A
GB2442774A GB0620169A GB0620169A GB2442774A GB 2442774 A GB2442774 A GB 2442774A GB 0620169 A GB0620169 A GB 0620169A GB 0620169 A GB0620169 A GB 0620169A GB 2442774 A GB2442774 A GB 2442774A
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United Kingdom
Prior art keywords
transistors
pair
coupled
complex impedance
emitters
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Withdrawn
Application number
GB0620169A
Other versions
GB0620169D0 (en
Inventor
Michael Schuck
Richard Krupa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Priority to GB0620169A priority Critical patent/GB2442774A/en
Publication of GB0620169D0 publication Critical patent/GB0620169D0/en
Priority to PCT/EP2007/060899 priority patent/WO2008043843A1/en
Publication of GB2442774A publication Critical patent/GB2442774A/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
    • H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
    • H03F3/195—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only in integrated circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G1/00—Details of arrangements for controlling amplification
    • H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
    • H03G1/0017—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier
    • H03G1/0023—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier in emitter-coupled or cascode amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/42—Modifications of amplifiers to extend the bandwidth
    • H03F1/48—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/4508—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using bipolar transistors as the active amplifying circuit
    • H03F3/45085—Long tailed pairs
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/4508—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using bipolar transistors as the active amplifying circuit
    • H03F3/45098—PI types
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/45179—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using MOSFET transistors as the active amplifying circuit
    • H03F3/45197—Pl types
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G1/00—Details of arrangements for controlling amplification
    • H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
    • H03G1/0035—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/24—Frequency-independent attenuators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/46—One-port networks
    • H03H11/48—One-port networks simulating reactances
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03878—Line equalisers; line build-out devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/36—Indexing scheme relating to amplifiers the amplifier comprising means for increasing the bandwidth
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/451—Indexing scheme relating to amplifiers the amplifier being a radio frequency amplifier
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45366—Indexing scheme relating to differential amplifiers the AAC comprising multiple transistors parallel coupled at their gates only, e.g. in a cascode dif amp, only those forming the composite common source transistor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45512—Indexing scheme relating to differential amplifiers the FBC comprising one or more capacitors, not being switched capacitors, and being coupled between the LC and the IC

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Amplifiers (AREA)

Abstract

An adjustable complex impedance circuit for gain slope control in a differential amplifier comprises two pairs of transistors T1,T2 and T2',T1', each pair having coupled emitters, cross-coupled bases and cross-coupled collectors. A control voltage Vslope is connected to the bases of the two pairs of transistors and the terminals A, A' of the circuit are connected to the collectors of the two pairs of transistors. The circuit further comprises two complex impedances Z1, Z2 (e.g. capacitors), a first complex impedance bridging the coupled emitters of a first pair of transistors with the terminal connected to said first pair of transistors and a second complex impedance bridging the coupled emitters of a second pair of transistors with the terminal connected to said second pair of transistors. The first and second complex impedances are arranged such that they comprise only alternating current paths.

Description

ELECTRONICALLY ADJUSTABLE GAIN SLOPE
CONTROLLER CIRCUIT
Field of the invention
The present invention relates to devices used for electronically conditioning of broadband signals at radio frequencies, in general, and in particular to circuits for compensating a frequency dependent attenuation of the signal.
Background of the Invention
A frequently encountered problem in transmission of broadband signals over a long transmission path is its frequency dependent attenuation, causing that signals at higher frequencies arrive much weaker at the destination point than signals at lower * frequencies. One possible solution for this problem is the use of amplifier circuits having a gain that increases with increasing frequency. Such a frequency response will *...
be called in the following text a gain slope. The gradient of the gain slope required to **. compensate the effects of the frequency dependent attenuation of the transmission line * : depends on the particular transmission path. ** * * * .
A known solution, used in electronically adjustment applications, is the use of a varactor element. Changing the DC voltage applied to the ports of a varactor causes changes in its capacitance. This effect allows for example the adjustments of resonant circuits in receivers.
A disadvantage of the solutions known in the art is that it is not possible to use a varactor in devices built in indium-gallium-phosphide (InGaP) technology. This technology is successfully used in high-power and high-frequency electronics that, in turn, is required for transmission of broadband signals if the broadband signals are to be delivered to receivers connected by long links. In solutions using varactors the shape control of the frequency response is limited, because only the capacitance is controlled, which results in less flexibility of the varactor solution.
Hence, an improved amplifier circuit would be advantageous and in particular one that is capable of compensating the frequency dependent attenuation and that can be manufactured in InGaP technology.
Summary of the Invention
Accordingly, the invention seeks to preferably mitigate, alleviate or eliminate one or more of the disadvantages mentioned above singly or in any combination.
According to a first aspect of the present invention there is provided an to adjustable complex impedance circuit for gain slope control as defined in claim 1.
The adjustable complex impedance circuit for gain slope control according to : *. the first aspect of the present invention comprises two pairs of transistors, each pair I...
having coupled their emitters, cross-coupled bases and cross-coupled collectors, e..
wherein a control voltage is connected to the bases of the two pairs of transistors and the operating contacts of the circuit are connected to the collectors of the two pairs of * S transistors. The circuit further comprises two complex impedances. A first complex impedance bridges the coupled emitters of a first pair of transistors with the operating contact connected to said first pair of transistors and a second complex impedance bridges the coupled emitters of a second pair of transistors with the operating contact connected to said second pair of transistors, wherein the two complex impedances comprise only alternating current paths.
According to a second aspect of the present invention there is provided a differential amplifier for compensating a frequency dependent attenuation of a signal as defined in claim 7.
The differential amplifier according to the second aspect of the present invention comprises a pair of transistors with emitters coupled via a resistor and connected in parallel to said resistor an adjustable complex impedance circuit for gain slope control.
The adjustable complex impedance circuit comprises two pairs of transistors, each pair having coupled their emitters, cross-coupled bases and cross-coupled collectors, wherein a control voltage is connected to the bases of the two pairs of transistors and the operating contacts of the circuit are connected to the collectors of the two pairs of transistors. The circuit further comprises two complex impedances. A first complex impedance bridges the coupled emitters of a first pair of transistors with the operating contact connected to said first pair of transistors and a second complex impedance bridges the coupled emitters of a second pair of transistors with the operating contact connected to said second pair of transistors, wherein the two complex impedances comprise only alternating current paths.
Further features of the present invention are as claimed in the dependent claims. * ** * * * **
The present invention beneficially allows for high flexibility of designing that allows for a specific frequency response (free choice of feedback impedance). The : invention is simply applicable to existing solutions while not adversely affecting ***** * existing performance. The solution can be used in devices manufactured in InGaP ** I : * technology as well as in silicon-gennanium (SiGe) and Complementary Metal-Oxide-Semiconductor (CMOS) technologies.
Brief description of the drawings
The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: FIG. 1 is a diagram illustrating a differential amplifier, FIG. 2 is a diagram illustrating an adjustable complex impedance; FIG. 3 is a diagram illustrating the differential amplifier of Fig. 1 with implemented adjustable complex impedance of Fig. 2; FIG. 4 is a diagram illustrating an adjustable complex impedance in one embodiment of the present invention; FIG. 5 is a diagram illustrating the principle of the adjustable complex impedance in one embodiment of the present invention; FIG. 6 is a diagram illustrating a frequency response of a hypothetical differential amplifier in one embodiment of the present invention; FIG. 7 is a diagram illustrating a differential amplifier with adjustable complex impedance of Fig. 4 in one embodiment of the present invention.
Description of embodiments of the invention
The present invention is discussed herein below in the context of bipolar transistors. However, it should be understood that it is not limited to bipolar transistors only, but instead applies as well as to Field-Effect Transistors (FET). Therefore where it is made reference to base, collector and emitter it should be understood that it equally : ** applies to gate, source and drain respectively. The solution disclosed below allows for **a* conditioning of broadband signals at radio frequencies, wherein the term "conditioning" relates to frequency selective power control by amplification or attenuation of the a mcoming signal.
S..... * a
In its main application the circuit disclosed in embodiments of the present invention is a sub-circuit in monolithic analogue amplifier devices. However, other applications, e.g. in form of discrete semiconductor components, are also possible.
The most widely used multiple transistor sub-circuit in monolithic analogue circuits for amplifier applications is the emitter-or source-coupled pair for bipolar transistors or FETs, respectively. One of the reasons for this frequent use is the differential input and/or output characteristics provided by this kind of transistor configuration. Amplifiers of this kind are commonly referred to as differential amplifiers.
The term AC (alternating current) path herein below refers to a transmission path in a circuit that is capable of transmitting AC signals only.
The term DC (direct current) path herein below refers to a transmission path in a circuit that is capable of transmitting DC signals only.
With reference to Fig. 1 a differential amplifier applying feedback technique is shown. If there is only resistor re connected between emitters of the transistors, the feedback characteristic of the circuit in Fig. I is mainly determined by the resistor r.
The typical frequency response in this case is a flat gain curve. If in parallel to the resistor re an adjustable complex impedance z(x) is added, then the frequency response of the amplifier can be controlled. As long as z(x) does not include a direct DC path, the gain for DC remains unchanged.
With reference to Fig. 2, the adjustable complex impedance is based on a circuit : **, comprising two cross coupled emitter-coupled pairs Ti-I'2 (a first pair) and I"1-T'2 (a ***.
second pair) as shown in Figure 2. In the two pairs of transistors, each pair has coupled is their emitters, cross-coupled bases and cross-coupled collectors. In practice, it means * that a first transistor, T, and a second transistor, I'2, have connected emitters and S....
* similarly a third and a fourth transistors T',, I"2, whereas collector of the first transistor l'j is connected to collector of the fourth transistor T'2 and base of the second transistor I'2 is connected to base of the fourth transistor I"2. Remaining contacts of the four transistors are connected in a similar fashion as it is illustrated in Fig. 2. The nodes A and A * of Fig. 2, referred to as operating contacts, are to be connected to the corresponding nodes in Fig. 1 instead of the impedance z(x).
In analysing the circuit of Fig. 2, when the base currents are ignored, it can be shown that for DC as well as for not to high frequencies the transistor currents 1,, 12, I', and I depend on the control voltage V as given by: I =I1+tanhiL)= I; 2L 2V) (1) i =Il_tanh__.')=1; 2 2 2V) where V7 is a thermal voltage and assuming that JE = 1E7. Equation (I) shows that for different values of the control voltage V the values of the currents vary between zero and JE whereas the sums of the currents I, and Ij as well as 1', and I'2 remain Constant at JE. Thus the difference of the currents A and A' is still zero. This is an important property of the control circuit, in terms of the linearity of the controlled amplifier.
* With reference to Fig. 3 the importance of said property is explained below. S.
The control circuit causes an additional current A and IA' in the Transistors T and *::* T respectively. The values of these currents are determined by the current sourceslE.
*: " Thus by appropriate choice of the values for JE and ee the designer can set the bias * conditions for the transistors Tand T' for best linear performance. These conditions are not affected by the values of the control voltage V, because the currents A and A' and therefore the currents I and I' are kept equal and constant. This condition is essential for high linearity, which would significantly be degraded in case of different values for I and!'.
The control circuit as shown in Fig. 2 and Fig. 3 does not change the slope of the amplifier gain by variation of the control voltage (expected for parasitic effects). This can be achieved by adding two impedances Z, and Z2 connected as shown in Fig. 4 and Fig. 7, which illustrate an adjustable complex impedance circuit for gain slope control according to one embodiment of the present invention (Fig. 4) and the same implemented in a differential amplifier for compensating a frequency dependent attenuation of a signal (Fig. 7). In one embodiment Z1 and Z2 can be equal, but in alternative embodiments Z1 and Z2 can have different values. As it is not necessary that Zj=Z2, this provides an additional degree of freedom allowing realization of complex gain slopes. A first complex impedance Z, bridges the coupled emitters of the first pair of transistors T, -1's with the operating contact A connected to said first pair of transistors 7', -T, and a second complex impedance Z2 bridging the coupled emitters of a second pair of transistors T', -T'2 with the operating contact A connected to said second pair of transistors T',-T'2.
The impedances Z, and Z2 do not include any DC path, thus in terms of DC analysis the circuit remains unchanged as compared to the circuit illustrated in Fig. 2 whereas for the AC component there are two additional paths, which can be controlled by the voltage : ,* In the scope of the amplifier shown in Fig. I both impedances Z1 and Z2 are parallel to the resistor re as illustrated in Fig. 5.
Adjusting the control voltage changes the weighting factor m, which I...
* defines bow strong the impedances Zj and Z2 act in the feedback of the amplifier. This changes the gain slope of the amplifier but not the characteristic properties of its frequency response. Fig. 6 shows this behaviour for a hypothetical amplifier, which in this particular embodiment was designed for the frequency range up to 1.5 0Hz. For m =0 the amplifier's gain is flat at 36 dB. With increasing value of m the gain slope raises by 4 dB and reaches 40 dB for 10Hz when m I. In one embodiment of the present invention the complex impedances Zi and Z2 comprise combination of resistance, inductance or capacitance elements. Depending on the requirements for the amplifier the impedances Zj and Z2 can consists of different real and reactive elements. The appropriate choice of these elements allows determining the shape of the frequency response of the whole amplifier circuit. The only restriction is that no DC path is allowed and any combinations of serial and parallel circuits consisting of resistance, inductance or capacitance elements as the complex impedances can be used. By any combination it is also understood using a single element (e.g. capacitor only) as said complex impedance.
In one embodiment, as illustrated in the appended figures, the transistors are of NPN type. However, in alternative embodiments it is possible to use transistors of PNP type (and their FET equivalents), but because holes are slower charge carriers than electrons, the transition frequency will be lower as in case of NPN transistors (and their FET equivalents).
In one embodiment it is possible, in case of the amplifier circuit, a combination that uses FETs in the adjustable impedance circuit and bipolar transistors in the differential amplifier circuit. It is also possible to use the opposite configuration, i.e. : *. FETs in amplifier and bipolar transistors in the adjustable impedance circuit. This gives s..
an additional flexibility in the slope of the control voltage and can be realized in BiCMOS-Technology. It is also with the contemplation of the present invention that the * invention can be implemented in Pseudomorphic High Electron Mobility Transistor * I.**I * (PHEMT). I. I * * . * I
The circuits in accordance with the embodiments of the present invention can be implemented in a Radio frequency Integrated Circuit (RFIC), which allows for an automatic gain control and an automatic slope control. Its primary, but not exclusive, use can be in Cable TV (CATV) and in Fibre to The Home (FTFH) applications.

Claims (13)

-- CLAIMS
1. An adjustable complex impedance circuit for gain slope control comprising two pairs of transistors (T, -I'
2 and T', -T), each pair having coupled their emitters, cross-coupled bases and cross-coupled collectors, wherein a control voltage <e) is connected to the bases of the two pairs of transistors (Tj-T2 and T',-T'2) and the operating contacts (A, A) of the circuit are connected to the collectors of the two pairs of transistors (I', -I'2 and T', -I"2) and further comprising two complex impedances (Zj, Z2), a first complex impedance (Z,) bridging the coupled emitters of a first pair of transistors (Ti-I'2) with the operating contact (A) connected to said first pair of transistors (Ti-Ti) and a second complex impedance (Z2) bridging the coupled emitters of a second pair of transistors (T',-T'2) with the operating contact (A) connected to said second pair of transistors (T, -I"2), wherein the two complex impedances (Zj, Z2) comprise only alternating current paths. * *.. * * ***.
* ... 2. The adjustable complex impedance according to claim I comprising Field-Effect *..* Transistors.
3. The adjustable complex impedance according to claim I comprising Heterojunction * * Bipolar Transistor.
4. The adjustable complex impedance according to any one of preceding claims, wherein the complex impedances (Z,, Z2) comprise any combination of resistance, inductance or capacitance elements.
5. The adjustable complex impedance according to claim 1 or claim 3 or claim 4 implemented in indium-gallium-phosphide or silicon-gennanium or Complementary Metal-Oxide--Semiconductor technologies.
6. The adjustable complex impedance according to claim 2 implemented in Complementary Metal-Oxide-Semiconductor technologies.
7. A differential amplifier for compensating a frequency dependent attenuation of a signal comprising a pair of transistors (7'-T) with emitters coupled via a resistor (re) and connected in parallel to said resistor (re) an adjustable complex impedance circuit for gain slope control comprising two pairs of transistors (Ti-i'2 and T'j-T'2), each pair having coupled their emitters, cross-coupled bases and cross-coupled collectors, wherein a control voltage (Vi, is connected to the bases of the two pairs of transistors (Tj-T, and T,-T'2) and the operating contacts (A, A') of the circuit are connected to the collectors of the two pairs of transistors (T, -T2 and T', -i"2) and further comprising two complex impedances (Z,. Z2), a first complex impedance (Z,) bridging the coupled emitters of a first pair of transistors (T, -T2) with the operating contact (A) connected to said first pair of transistors (T, -i'2) and a second complex impedance (Z2) bridging the coupled emitters of a second pair of transistors (T'1 -T) with the operating contact (A) connected to said second pair of transistors (Ti-T'2), wherein the two complex impedances (Z,, Z2) comprise only alternating current paths. e..
S *SSS
8. The amplifier according to claim 7, wherein the adjustable complex impedance S...
* circuit comprises Field-Effect Transistors.
*SS*.S * S
9. The amplifier according to claim 7 or claim 8, comprising Field-Effect Transistors.
S..... * S
10. The amplifier according to claim 7, wherein the adjustable complex impedance circuit comprises Heterojunction Bipolar Transistor.
11. The amplifier according to claim 7 or claim 8 or claim 10, comprising Heterojunction Bipolar Transistor.
12. The amplifier according to any one of claims 7-11, wherein the complex impedances (Z,, Z2) comprise combination of resistance, inductance or capacitance elements.
13. The amplifier according to any one of claims 7 -12 implemented in indium-gallium-phosphide or silicon-germanium or Complementary Metal-Oxide-Semiconductor technologies. * ** * * * * S **** S... * S S...
a..... * S S. S S S * * S *
**.*.. * .
GB0620169A 2006-10-12 2006-10-12 Electronically adjustable gain slope controller circuit Withdrawn GB2442774A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB0620169A GB2442774A (en) 2006-10-12 2006-10-12 Electronically adjustable gain slope controller circuit
PCT/EP2007/060899 WO2008043843A1 (en) 2006-10-12 2007-10-12 Electronically adjustable gain slope controller circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0620169A GB2442774A (en) 2006-10-12 2006-10-12 Electronically adjustable gain slope controller circuit

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GB0620169D0 GB0620169D0 (en) 2006-11-22
GB2442774A true GB2442774A (en) 2008-04-16

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115580246B (en) * 2022-12-07 2023-05-23 西安博瑞集信电子科技有限公司 Positive slope gain amplifier based on two-stage amplification

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986007508A1 (en) * 1985-06-03 1986-12-18 Motorola, Inc. Balanced variable reactance circuit and method of producing the same
EP0602723A1 (en) * 1992-12-15 1994-06-22 Koninklijke Philips Electronics N.V. Integrated circuit with an electrically adjustable parameter
US5786726A (en) * 1995-10-31 1998-07-28 U.S. Philips Corporation Device of the phase-locked loop type for demodulating a frequency-modulated signal

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000299619A (en) * 1999-03-02 2000-10-24 Trw Inc Monolythic fixed active equalizer
JP2005142633A (en) * 2003-11-04 2005-06-02 Mitsubishi Electric Corp Differential amplifier circuit and multi-stage amplifier circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986007508A1 (en) * 1985-06-03 1986-12-18 Motorola, Inc. Balanced variable reactance circuit and method of producing the same
EP0602723A1 (en) * 1992-12-15 1994-06-22 Koninklijke Philips Electronics N.V. Integrated circuit with an electrically adjustable parameter
US5786726A (en) * 1995-10-31 1998-07-28 U.S. Philips Corporation Device of the phase-locked loop type for demodulating a frequency-modulated signal

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WO2008043843A1 (en) 2008-04-17

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