USRE39949E1 - Sound intermediate frequency amplifier for a broadcast receiver - Google Patents
Sound intermediate frequency amplifier for a broadcast receiver Download PDFInfo
- Publication number
- USRE39949E1 USRE39949E1 US11/064,521 US6452105A USRE39949E US RE39949 E1 USRE39949 E1 US RE39949E1 US 6452105 A US6452105 A US 6452105A US RE39949 E USRE39949 E US RE39949E
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- United States
- Prior art keywords
- operating voltage
- voltage
- transistor
- source
- intermediate frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- 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
- H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
- H03F1/305—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in case of switching on or off of a power supply
Definitions
- the invention relates to a sound intermediate frequency amplifier according to the introductory part of claim 1 .
- the invention relates to a sound intermediate frequency amplifier for a broadcast receiver including an IC having an operating voltage terminal connected to a source of a dc operating potential.
- the invention consists in that said dc source is connected to said terminal via the collector/emitter-path of a transistor and that a second source of operating potential is connected via a RC integrating network to the base of said transistor, the base being connected to ground via a zener diode.
- a resistor is provided between said transistor and said operating voltage terminal of said IC, whereas the operating voltages are derived by rectification of the output pulse voltage of the line fly-back transformer of a television receiver.
- the circuit of the invention fulfils two objects simultaneously.
- the circuit prevents a sudden change in operating voltage fed to IC and provides a soft or smooth increase in operating voltage during switch on of the receiver.
- the circuit effects an additional stabilization of the operating voltage fed to the sound intermediate frequency amplifier IC by the action of said diode. So very good results are achieved by a rather simple circuit which generally includes only one transistor, one resistor, one capacitor and one zener diode.
- FIG. 1 shows a sound intermediate frequency amplifier together with the circuit according to the invention
- FIG. 2 waweforms for illustrating the function of the circuit according to FIG. 1 .
- an antenna 1 is connected to a tuner 2 of a television receiver.
- Output of tuner 2 is connected to a sound intermediate frequency amplifier and audio amplifier IC 3 .
- IC 3 among other terminals has an operating voltage terminal 11 for supplying a dc operating voltage thereto and a terminal 10 providing output audio frequency signal which is fed via an audio amplifier 4 to loudspeaker 5 for sound reproduction.
- Operating voltage U 1 for IC 3 is supplied via the collector/emitter-path of a transistor T 1 and resistor R 1 to terminal 11 which is further connected to ground via capacitor C 1 .
- a second dc operating voltage U 2 is connected via integrating circuit with resistor R 2 and capacitor C 2 to base of transistor T 1 , the base being connected to ground via zener diode Z 1 .
- dc voltages U 1 and U 2 may be generated by rectification of the pulse voltage at the line output transformer of the television receiver.
- the circuit according to FIG. 1 solves the “POP” sound problem and also helps to stabilize the dc supply voltage for SIF-IC 3 .
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
- Television Receiver Circuits (AREA)
Abstract
In a broadcast receiver, a dc voltage operating source is coupled to an operating voltage terminal of a sound IF integrated circuit via a collector/emitter path of a transistor, and a second source of operating voltage is connected via an RC integrating network to the base of the transistor, with the base of the transistor being connected to ground via a zener diode.
Description
The invention relates to a sound intermediate frequency amplifier according to the introductory part of claim 1.
Within a television receiver during a switching from “OFF” to “ON” or switching from “Stand-by” to “ON” audible disturbance within the reproduced sound occurs, which is generally called “POP”. This disturbances in form of a click is due to a sudden change in the operating voltage fed to the sound intermediate frequency amplifier IC. According to prior art capacitors are introduced to prevent such a sudden change in operating voltage. However such known circuits operates not sufficiently so that in most cases an indesirable “POP” remains.
It is an object of the invention to modify the circuit for the sound intermediate frequency amplifier in such a way that such disturbances in audio reproduction like “POP” do not occur or remain inaudible.
The invention relates to a sound intermediate frequency amplifier for a broadcast receiver including an IC having an operating voltage terminal connected to a source of a dc operating potential. Within such an amplifier the invention consists in that said dc source is connected to said terminal via the collector/emitter-path of a transistor and that a second source of operating potential is connected via a RC integrating network to the base of said transistor, the base being connected to ground via a zener diode. In a preferred embodiment of the invention a resistor is provided between said transistor and said operating voltage terminal of said IC, whereas the operating voltages are derived by rectification of the output pulse voltage of the line fly-back transformer of a television receiver.
The circuit of the invention fulfils two objects simultaneously. On one hand the circuit prevents a sudden change in operating voltage fed to IC and provides a soft or smooth increase in operating voltage during switch on of the receiver. On the other hand the circuit effects an additional stabilization of the operating voltage fed to the sound intermediate frequency amplifier IC by the action of said diode. So very good results are achieved by a rather simple circuit which generally includes only one transistor, one resistor, one capacitor and one zener diode.
In order that the invention may be better understood and easily carried out into practice an embodiment of the invention is described in connection with an accompanying drawing. In the drawing
In FIG. 1 an antenna 1 is connected to a tuner 2 of a television receiver. Output of tuner 2 is connected to a sound intermediate frequency amplifier and audio amplifier IC 3. IC 3 among other terminals has an operating voltage terminal 11 for supplying a dc operating voltage thereto and a terminal 10 providing output audio frequency signal which is fed via an audio amplifier 4 to loudspeaker 5 for sound reproduction.
Operating voltage U1 for IC 3 is supplied via the collector/emitter-path of a transistor T1 and resistor R1 to terminal 11 which is further connected to ground via capacitor C1. A second dc operating voltage U2 is connected via integrating circuit with resistor R2 and capacitor C2 to base of transistor T1, the base being connected to ground via zener diode Z1.
In connection with FIG. 2 the operating of the circuit according to FIG. 1 is explained. From t1 to t2 television receiver is switched off so that voltage U3 at terminal 11 is zero and no output voltage is fed from terminal 10 to amplifier 4. At t2 the television receiver is switched on from “OFF” status of “stand-by” status. Waveform A shows a sudden rise or jump within voltage U3 at terminal 11, said jump generating the indesired POP at loudspeaker 5. In the circuit according to FIG. 1 at t2 capacitor C2 is unloaded so that voltage at base of T1 is zero so that short after t2 T1 is cut off and U3 cannot make the sudden change or jump as in the waveform A. After t2 capacitor C2 is charged via R2 so that the voltage at base of T1 increases in positive direction. T1 becomes conductive so that also U3 increases smoothly according to waveform B. At t3 voltage U3 reaches the final value which is the same at the final value of waveform A. It can be seen that the sudden change or jump of waveform A which is a reason for undesired POP is avoided and undesired POP occurs not at loudspeaker 5.
At t3 voltage at base of T1 reaches the zener voltage of Z1 and cannot further increase. As the voltage at the emitter of T1 always remains closely to the voltage at base of T1 by a difference of the emitter to base voltage of about 0.7 V, voltage at the emitter of T1 and so voltage U3 is stabilized by the action of zener diode Z1. Any variation in U1 therefore are compensated so that the IC 3 is always supplied at terminal 11 with a constant stabilized dc operating potential U3.
In a television receiver dc voltages U1 and U2 may be generated by rectification of the pulse voltage at the line output transformer of the television receiver. Hence, the circuit according to FIG. 1 solves the “POP” sound problem and also helps to stabilize the dc supply voltage for SIF-IC 3.
Within a practical tested circuit according to FIG. 1 the elements shown in FIG. 1 had the following values:
-
- R1: 1,2 Ohm
- R2: 2,2 kOhm
- CI: 47 mikroF
- C2: 470 mikroF
- T1: type BC637
- Z1: type ZPD13
- U1: +13 V
- U2: +25 V
Claims (3)
1. A sound intermediate frequency amplifier for a broadcast receiver comprising;
an integrated circuit having an operating voltage terminal connected to a first source of a dc operating voltage, said operating voltage terminal being connected to ground via a capacitor,
said first source of operating voltage is connected to said operating voltage terminal via a collector-emitter path of a transistor, and
a second source of operating voltage is connected via a RC integrating network to a base of said transistor, the base being connected to ground via a zener diode.
2. The amplifier according to claim 1 , wherein a resistor is provided between said transistor and said operating voltage terminal.
3. The amplifier according to claim 1 , wherein said second source of operating voltage is higher than said first source of operating voltage.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/064,521 USRE39949E1 (en) | 1992-03-25 | 2005-05-02 | Sound intermediate frequency amplifier for a broadcast receiver |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP92400816 | 1992-03-25 | ||
US08/029,277 US5426394A (en) | 1993-03-12 | 1993-03-12 | Sound intermediate frequency amplifier for a broadcast receiver |
US11/064,521 USRE39949E1 (en) | 1992-03-25 | 2005-05-02 | Sound intermediate frequency amplifier for a broadcast receiver |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/029,277 Reissue US5426394A (en) | 1992-03-25 | 1993-03-12 | Sound intermediate frequency amplifier for a broadcast receiver |
Publications (1)
Publication Number | Publication Date |
---|---|
USRE39949E1 true USRE39949E1 (en) | 2007-12-25 |
Family
ID=21848176
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/029,277 Ceased US5426394A (en) | 1992-03-25 | 1993-03-12 | Sound intermediate frequency amplifier for a broadcast receiver |
US11/064,521 Expired - Lifetime USRE39949E1 (en) | 1992-03-25 | 2005-05-02 | Sound intermediate frequency amplifier for a broadcast receiver |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/029,277 Ceased US5426394A (en) | 1992-03-25 | 1993-03-12 | Sound intermediate frequency amplifier for a broadcast receiver |
Country Status (1)
Country | Link |
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US (2) | US5426394A (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5936470A (en) * | 1997-12-10 | 1999-08-10 | Delco Electronics Corporation | Audio amplifier having linear gain control |
DE19858836A1 (en) * | 1998-12-19 | 2000-06-21 | Bayerische Motoren Werke Ag | Vehicle audio system has separate amplifier for low audio frequencies supplied with significantly higher operating voltage than amplifier(s) for other audio frequencies |
JP2005117618A (en) * | 2003-09-19 | 2005-04-28 | Sharp Corp | Integrated circuit and optical pickup device |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3798559A (en) * | 1971-04-20 | 1974-03-19 | Matsushita Electric Ind Co Ltd | Noise reduction system |
DE2854196A1 (en) * | 1978-12-15 | 1980-06-26 | Bosch Gmbh Robert | Switching delay circuit for amplifier network - has controllable transistors connected in signal path from end stage transistorised circuit |
GB2096423A (en) * | 1981-04-06 | 1982-10-13 | Philips Nv | Amplifier comprising means for avoiding direct voltage transients on the amplifier output |
EP0069843A1 (en) * | 1981-07-10 | 1983-01-19 | Deutsche Thomson-Brandt GmbH | LF amplifier for a television receiver |
DE3244254C1 (en) * | 1982-11-30 | 1984-03-15 | Deutsche Thomson-Brandt Gmbh, 7730 Villingen-Schwenningen | Circuit for muting control of an AF power amplifier on activation and deactivation |
US4481462A (en) * | 1981-12-17 | 1984-11-06 | U.S. Philips Corporation | Amplitude control system |
US4633188A (en) * | 1984-11-21 | 1986-12-30 | Alps Electric Co., Ltd. | Mixer/amplifier circuit |
US4956616A (en) * | 1988-06-02 | 1990-09-11 | Sgs-Thomson Microelectronics S.R.L. | Muting circuit for audio amplifiers |
-
1993
- 1993-03-12 US US08/029,277 patent/US5426394A/en not_active Ceased
-
2005
- 2005-05-02 US US11/064,521 patent/USRE39949E1/en not_active Expired - Lifetime
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3798559A (en) * | 1971-04-20 | 1974-03-19 | Matsushita Electric Ind Co Ltd | Noise reduction system |
DE2854196A1 (en) * | 1978-12-15 | 1980-06-26 | Bosch Gmbh Robert | Switching delay circuit for amplifier network - has controllable transistors connected in signal path from end stage transistorised circuit |
GB2096423A (en) * | 1981-04-06 | 1982-10-13 | Philips Nv | Amplifier comprising means for avoiding direct voltage transients on the amplifier output |
EP0069843A1 (en) * | 1981-07-10 | 1983-01-19 | Deutsche Thomson-Brandt GmbH | LF amplifier for a television receiver |
US4481462A (en) * | 1981-12-17 | 1984-11-06 | U.S. Philips Corporation | Amplitude control system |
DE3244254C1 (en) * | 1982-11-30 | 1984-03-15 | Deutsche Thomson-Brandt Gmbh, 7730 Villingen-Schwenningen | Circuit for muting control of an AF power amplifier on activation and deactivation |
US4633188A (en) * | 1984-11-21 | 1986-12-30 | Alps Electric Co., Ltd. | Mixer/amplifier circuit |
US4956616A (en) * | 1988-06-02 | 1990-09-11 | Sgs-Thomson Microelectronics S.R.L. | Muting circuit for audio amplifiers |
Non-Patent Citations (5)
Title |
---|
RCA/GE Color Television Basic Service Data CTC 169(DV), published by Thomson Consumer Electronics, Inc., Indianapolis, Ind. in 1990, pp. 2-G-1. * |
Translation of "AL" Previously Disclosed on Mar. 11, 1993 of Ger.2854196. * |
Translation of "AM" Previously Disclosed on Mar. 11, 1993 of EPO 0069843. * |
Translation of "AN" Previously Disclosed on Mar. 11, 1993 or Ger.3244254. * |
U.S. Appl. No. 07/703,107, filed May 5, 21, 1991, for M. R. Anderson et al. * |
Also Published As
Publication number | Publication date |
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US5426394A (en) | 1995-06-20 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: THOMSON LICENSING, FRANCE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:THOMSON LICENSING S.A.;REEL/FRAME:019516/0188 Effective date: 20070703 |