GB2081541A - Muting radio receiver - Google Patents
Muting radio receiver Download PDFInfo
- Publication number
- GB2081541A GB2081541A GB8121414A GB8121414A GB2081541A GB 2081541 A GB2081541 A GB 2081541A GB 8121414 A GB8121414 A GB 8121414A GB 8121414 A GB8121414 A GB 8121414A GB 2081541 A GB2081541 A GB 2081541A
- Authority
- GB
- United Kingdom
- Prior art keywords
- radio receiver
- circuit
- volume control
- muting
- control voltage
- 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.)
- Withdrawn
Links
- 238000010586 diagram Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
- H03G3/348—Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Control Of Amplification And Gain Control (AREA)
- Noise Elimination (AREA)
- Circuits Of Receivers In General (AREA)
Abstract
A radio receiver which comprises an electronic volume control circuit (6), an audio amplifier (7) to be controlled by the volume control circuit, a control voltage generating circuit (20) for generating a voltage (V) to control the volume control circuit and a muting signal source. The control voltage generating circuit is arranged to generate a voltage to make the attenuation of the volume control circuit largest when a muting signal is applied to the control circuit from the muting signal source during tuning operation and accordingly to apply the control voltage to the volume control circuit. The muting signal may be applied to a transistor (Q) in the control voltage generating circuit (20) through a delay circuit (R1, C1 Fig. 5). <IMAGE>
Description
SPECIFICATION
Radio receiver
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a radio receiver, and more particularly to improvements in a muting mechanism in a radio receiver of electronic tuning system having an electronic volume control circuit in a low frequency amplifier.
Description of the Prior Art
A conventional electronic tuning radio receiver has been constructed as shown in Fig.
1. The reference numeral 1 designates an antenna, 2 a high frequency amplifier, 3 a mixing circuit, 4 an intermediate frequency amplifier, 5 a low frequency amplifier comprising an electronic control circuit 7 and an audio amplifier 7, and, 8 a loudspeaker, respectively. Further, the reference numeral 9 designates a PLL circuit for applying local oscillation signals for tuning to the mixing circuit 3. The PLL circuit 9 comprises a reference oscillator 10, a control circuit 11, a program divider 12, a phase comparator 13, a low pass filter 14 and a voltage control oscillator 15.
With this arrangement, in order to eliminate noise such as interoffice noises, there has been proposed the following mechanism. That is, a muting circuit 1 6 is provided in front of the low frequency amplifier 5 as shown in
Fig. 2 and it is actuated to attenuate audio signals from the intermediate amplifier 4 when a muting signal is applied to a terminal 1 7 from the control circuit 11 during tuning operation.
However, to provide a muting circuit as above causes the circuit arrangement to be complicated. Particularly when there exist a plurality of audio signal sources, circuit will be extremely complicated to thereby causes increase of the production cost.
OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide a radio receiver in which, by providing a control voltage generating circuit for generating a voltage for controlling a electronic volume control circuit, attenuation of the electronic volume control circuit becomes largest when a muting signal is applied.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a radio receiver which comprises:
a volume control means for controlling volume of received signals;
a means for generating muting signals during tuning operation of the radio receiver; and
a control voltage generating means for generating a control voltage to make attenuation of said volume control means largest and thereby applying it to said volume control means.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a block diagram illustrating a structure of an electronic tuning radio receiver;
Figure 2 shows a block diagram illustrating a conventional mechanism;
Figure 3 and Figure 5 each shows a circuit diagram illustrating an embodiment according to the present invention;
Figure 4 is a graph showing characteristics of the control voltage generating circuit.
DETAILED DESCRIPTION OF THE PRE
FERRED EMBODIMENTS
The present invention will now be described in detail referring to the preferred embodiments illustrated in the accompanying drawings.
Fig. 3 shows a circuit diagram illustrating an embodiment according to the present invention in which same reference numerals and symbols are used to designate substantially same or similar circuits to those in Figs. 1 and 2. The reference symbol Q is a transistor, VR is volume, 1 8 is a muting signal input terminal, 1 9 is an input terminal to which a reference voltage Vref is applied from the reference voltage source 19' and they all construct a control voltage generating circuit 20. It is the control circuit 11 that applies a muting signal to the terminal 1 8.
The control voltage generating circuit 20 generates a control voltage V which is consequently applied to the electronic volume control circuit 6. Thereby, the attenuation of the volume control circuit can be adjusted by varying the above control voltage. Incidentally, Fig. 4 shows the characteristics of the control voltage generating circuit 20 in which the abscissa is control voltage and the ordinate is attenuation.
In Fig. 3, when a muting signal applied to the terminal 18, the transistor 0 is turned on to thereby put out a voltage of about OV.
Thus, the control voltage comes out OV and accordingly the attenuation of the electronic volume control circuit 6 is controlled to be largest, thus creating a muting condition.
When a muting signal is not applied, the reference voltage V can be set at a desired value of a range from 0 to the reference voltage Vref by varying the volume VR. Accordingly, the attenuation of the electronic volume control circuit 6 also can be set at a desired value.
Fig. 5 illustrates another embodiment according to the present invention. In this embodiment, there are provided resistors R1, R2 and R3 in the control voltage generating circuit 20 as well as a delay circuit having a capacity C,. With this arrangement, it is made possible to smoothly vary the reference voltage V generated by the transistor Q when a muting signal applied to the terminal 18.
Therefore, thus allowing degree of the muting to be smoothly controlled by the volume control circuit 6.
As apparent from the above description, according to the present invention there are provided a control voltage generating circuit for controlling attenuation of an electronic volume control circuit so that the largest attenuation is obtained when a muting signal is applied and it is made possible to set the control voltage generating circuit at a desired attenuation value when a muting signal is not applied. Therefore, muting operation can be carried out with such a simple circuit structure without requiring a muting circuit as conventionally used. That is, the present invention has such advantages not only of reducing production cost but also of simplifying attenuation setting constant.
Claims (5)
1. A radio receiver which comprises:
a volume control means for controlling volume of received signals;
a means for generating muting signals during tuning operation of the radio receiver; and
a control voltage generating means for generating a control voltage to make attenuation of said volume control means largest and thereby applying it to said volume control means.
2. The radio receiver as claimed in Claim 1, wherein said control voltage generating means includes at least one transistor connected to said volume control means at one end thereof and grounded at the other end thereof to thereby turns on in response to said muting signal.
3. The radio receiver as claimed in Claim 2, wherein said control voltage generating means further includes a variable resistor and a reference voltage source connected to send variable resistor, output voltage from said variable resistor being applied to said volume control means.
4. The radio receiver as claimed in Claim 2 further comprising a delay circuit connected to the base of said transistor, said muting signal being applied to said transistor through said delay circuit.
5. A radio receiver substantially as herein described with reference to and as shown in
Figs. 3 to 5 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9803480U JPS5723009U (en) | 1980-07-14 | 1980-07-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2081541A true GB2081541A (en) | 1982-02-17 |
Family
ID=14208740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8121414A Withdrawn GB2081541A (en) | 1980-07-14 | 1981-07-10 | Muting radio receiver |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5723009U (en) |
| DE (1) | DE3127815A1 (en) |
| FR (1) | FR2486736A1 (en) |
| GB (1) | GB2081541A (en) |
| NL (1) | NL8103330A (en) |
| SE (1) | SE8104323L (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0219920A2 (en) * | 1985-10-24 | 1987-04-29 | Philips Patentverwaltung GmbH | Circuit arrangement for an amplifier to suppress noise at minimum loudness level |
| EP0590706A1 (en) * | 1992-10-01 | 1994-04-06 | Delco Electronics Corporation | Amplifier apparatus |
| US5440702A (en) * | 1992-10-16 | 1995-08-08 | Delco Electronics Corporation | Data processing system with condition code architecture for executing single instruction range checking and limiting operations |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3882400A (en) * | 1972-11-27 | 1975-05-06 | Sony Corp | Broadcast receiver |
| DE2547038C3 (en) * | 1975-10-21 | 1978-10-12 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Method and arrangement for reducing reception interference in radio receivers caused by switching processes |
| US4207530A (en) * | 1977-09-12 | 1980-06-10 | Motorola, Inc. | Electrically tunable inductor and method |
| JPS5535584A (en) * | 1978-09-06 | 1980-03-12 | Matsushita Electric Ind Co Ltd | Sound volume controller |
-
1980
- 1980-07-14 JP JP9803480U patent/JPS5723009U/ja active Pending
-
1981
- 1981-07-10 FR FR8113716A patent/FR2486736A1/en active Granted
- 1981-07-10 GB GB8121414A patent/GB2081541A/en not_active Withdrawn
- 1981-07-13 SE SE8104323A patent/SE8104323L/en not_active Application Discontinuation
- 1981-07-13 NL NL8103330A patent/NL8103330A/en not_active Application Discontinuation
- 1981-07-14 DE DE19813127815 patent/DE3127815A1/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0219920A2 (en) * | 1985-10-24 | 1987-04-29 | Philips Patentverwaltung GmbH | Circuit arrangement for an amplifier to suppress noise at minimum loudness level |
| EP0219920A3 (en) * | 1985-10-24 | 1988-08-24 | Philips Patentverwaltung GmbH | Circuit arrangement for an amplifier to suppress noise at minimum loudness level |
| EP0590706A1 (en) * | 1992-10-01 | 1994-04-06 | Delco Electronics Corporation | Amplifier apparatus |
| US5440702A (en) * | 1992-10-16 | 1995-08-08 | Delco Electronics Corporation | Data processing system with condition code architecture for executing single instruction range checking and limiting operations |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3127815A1 (en) | 1982-04-08 |
| FR2486736A1 (en) | 1982-01-15 |
| SE8104323L (en) | 1982-01-15 |
| NL8103330A (en) | 1982-02-01 |
| JPS5723009U (en) | 1982-02-05 |
| FR2486736B1 (en) | 1984-06-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |