GB2187906A - Electronic tuners - Google Patents
Electronic tuners Download PDFInfo
- Publication number
- GB2187906A GB2187906A GB08704179A GB8704179A GB2187906A GB 2187906 A GB2187906 A GB 2187906A GB 08704179 A GB08704179 A GB 08704179A GB 8704179 A GB8704179 A GB 8704179A GB 2187906 A GB2187906 A GB 2187906A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tuning
- voltages
- channel
- local oscillator
- circuits
- 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- Withdrawn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
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
- H03J5/02—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with variable tuning element having a number of predetermined settings and adjustable to a desired one of these settings
- H03J5/0245—Discontinuous tuning using an electrical variable impedance element, e.g. a voltage variable reactive diode, in which no corresponding analogue value either exists or is preset, i.e. the tuning information is only available in a digital form
- H03J5/0254—Discontinuous tuning using an electrical variable impedance element, e.g. a voltage variable reactive diode, in which no corresponding analogue value either exists or is preset, i.e. the tuning information is only available in a digital form the digital values being transfered to a D/A converter
- H03J5/0263—Discontinuous tuning using an electrical variable impedance element, e.g. a voltage variable reactive diode, in which no corresponding analogue value either exists or is preset, i.e. the tuning information is only available in a digital form the digital values being transfered to a D/A converter the digital values being held in an auxiliary non erasable memory
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/28—Continuous tuning of more than one resonant circuit simultaneously, the tuning frequencies of the circuits having a substantially constant difference throughout the tuning range
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
- H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
- H03J1/0033—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for voltage synthesis with a D/A converter
Abstract
An electronic tuner for use in a television receiver or a video tape recorder has a plurality of tuning circuits 1 to 3 and a local oscillator circuit 4. Each circuit includes a varactor diode 13, 23, 33, 43. The tuner is equipped with a memory 7 in which information concerning voltages for selecting each channel is stored. These voltages are set for the tuning frequencies of the tuning circuit 1 to 3 and for the frequency of the local oscillator circuit 4 for each channel. When a channel is selected, the voltages are supplied to the tuning circuits 1 to 3 and the local oscillator circuit 4, respectively, in accordance with the information which is read from the memory according to the selected channel. <IMAGE>
Description
SPECIFICATION
Electronic tuner
The present invention relates to electronic tuners.
Electronic tuners are able to select signals having a particularfrequency in a shorttime by electronic tuning.
Generally, an electronic tunerfor use in a television receiver, video tape recorder, orthe like comprises tuning circuits each consisting of a parallel resonant circuit made up ofavaractordiode and an inductance.
It is an object ofthe present invention to provide an improved electronic tuner.
According to the present invention there is provided an electronictunercomprising: tuning circuits each includingavaractordiode; a local oscillator circuit including a varactor diode; and a storage device in which information concerning voltages for selecting each channel is stored, the voltages being set for the tuning frequencies ofthetuning circuits and for the frequency of the local oscillator circuit for each channel, the voltages being applied to thetuning circuits andthe local oscillator circuit, respectively, in accordance with the information which is read from the storage device according to the selected channel.
The storage device is provided to store information concerning voltages for selecting each channel, the voltages being set for the tuning circuits and the local oscillator circuit, respectively, so as to correspond to the tuning frequencies and the frequency ofthe local oscillatorcircuitforthe selected channel. The voltages are applied to the tuning circuits and the local oscillator circuit in accordance with the information which is read from the storage device according to the selected channel.Therefore, DC voltages are applied tothetuning circuits and the local oscillator circuit having varactordiodes and inductanceswhich differ in characteristics, in order to produce certain tuning frequencies and a certain local oscillatorfrequencyfor each channel received. Consequently, neither the selection of matched varactor diodes nor tracking is necessary, unlike the conventional tuners. Additionally, because information concerning voltages for selecting a channel is read from the storage device, and because DC voltages according to the information are applied tothetuning circuits and the local oscil lator circuit, the detection of the sig nal levels of intermediate fequencies is not needed, unlike the conventional tuners.Also, the novel tuner can select any desired channel in a shorttime. Furthermore, no malfunction takes place if the electric field strength varies during tuning.
An electronic tuner embodying the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which:
Fig. lisa circuit diagram ofthe main portions of an electronictuner embodying the invention;
Fig. 2 isa circuit diagram ofthe main portions of a previously proposed electronictuner; and
Fig. 3 is a circuit diagram ofthe main portions of another previously proposed electronic tuner.
Fig. 2 is a circuit diagram ofthe main portions of a previous proposed electronictuner. This tuner com- prises atuning circuit 1 inthe antenna stage disposed before an RFamplifierelement(notshown),an RF tuning circuit 2 disposed afterthe RF amplifier element, a mixertuning circuit 3 disposed before a mixer (not shown), and a local oscillatortuning circuit 4 connected to a local oscillator element (not shown).
The RFtuning circuit 2 and the mixertuning circuit3 are coupled togetherto form a double-tuned circuit.
The local oscillator element and the oscillatortuning circuit4forma localoscillatorcircuit.Thetuning circuit 1 consists of an inductance 11,tracking capacitors 12,15 and a varactor diode 13. Similarly, thetuning circuit2 is composed of an inductance 21, tracking capacitors22,25 and a varactor diode 23. The tuning circuit3 comprises an inductance3l,tracking capacitors 32,35 and a varactor diode 33. The tuning circuit4 consists of an inductance 41,tracking capacitors 42,45 and a varactor diode 44. A DC voltage from a DC power supply 5 which is adjusted by a potentiometer 51 or the like is applied to the varactor diodes 13,23,33,43 via resistors 14,24,34,44, respectively.
In the operation ofthe structure constructed as described above, the potentiometer 51 is adjusted according to the selected channel. Thus, the DC voltage from the power supply 5 is adjusted to adjust thetuningfrequencyofthetuningcircuits to4.
Thetuningfrequencyofthetuning circuits 1,2,3 must always be kept constant as long as one channel is received. Also, the tuning frequency ofthe oscillator tuning circuit4 must invariably be keptatan intermediate frequency apartfrom that frequency.
Therefore, varactor diodes whose characteristics are identical within the range of variations of the applied
DC voltage are selected as the varactor diodes 13,23, 33,43. However, even if the diodes 13,23,33,43 are selected in this way, desired frequencies cannot always be achieved because of variations ofthe capacitances developed atthe input and the output of the RF ampliferelement connected aroundthevarac- tor diodes, variations ofthe capacitances developed at the inputs ofthe mixer element and ofthe local oscillator element, variations of the inductances 11, 21,31,41 and the stray capacitance and the stray inductance due to the tolerance produced at the time of assembly. For this reason,tracking is needed.That is, the tracking capacitors 12, 15,22,25,32,35,42,45 and the inductances 11,21,31,41 are adjusted to correct the tuning characteristics. In spite ofthis tracking, it is difficult to make an accurate adjustment over the entire range of received frequencies. Hence, the band characteristics may vary, depending on the received channel. This introduces the disadvantage thatthe image quality is not maintained constant.
Another problem arises from the fact that the tracking capacitors 15,25,35,45 are placed in parallel with the varactordiodes 13,23,33,43, so that thetuning range is narrow. Consequently, a satisfactory result has not been obtained.
In an attempt to avoid the difficulties with the electronic tuner shown in Fig. 2, another electronic tuner has been proposed. The main portions of th is proposed tuner are shown in Fig. 3, and this tuner is similartothetunershown inFig.2exceptforthe following.
In thetuner shown in Fig. 3, different DC voltages are applied to the tuning circuits 1 to 4.Thetuning- frequency signals delivered from the antenna tuning circuit 1,the RFtuning circuit 2, andthemixertuning circuit 3 are applied to level comparatorcircuits 19,29, 39, respectively,thatare used to detectthose DC voltages which make the tuning frequencies coincide with their respective intermediate frequencies, producing the greatest intermediate-frequency signal levels. As an example, a narrow-band filter whose centrefrequency coincides with an intermediate frequency is used.The output signal from the filter is fed directly to a comparator and also to itvia a delay circuit. As the DC voltages applied to the varactor diodes 13,23,33 are swept, the signal levels ofthe intermediate frequencies increase or decrease. The maximum DC voltages which produce the maximum levels of the intermediate frequencies are detected.
The tuning-frequency signal delivered from the oscillatortuning circuit4 issuppliedto a phase comparator circuit 8, which determines whetherthe tuning frequency coincides with a certain local oscillator frequency. A controller6 supplies different digital signals to digital-to-analog converters 16,26,36,46.
The DC voltages from the converters 16,26,36,46 are fed to the varactor diodes 13,23,33,43, respectively, to adjustthe tuning frequencies ofthe tuning circuits to 4. The controller 6 sweeps the digital signals furnished to the DIA converters 16,26,36. The sweep ofthe digital signals is stopped in response to the output signals from the level comparator circuits 19, 29,39 to trackthetuning circuits 1 to 3. The controller 6 also adjusts the tuning frequency ofthe oscillator tuning circuit4to a certain local oscillatorfrequenacy in response to the output signal from the phase comparator 8.
In the electronic tuner shown in Fig. 3, the tuning circuits 1 to 4 are separately adjusted. Therefore it is notnecessaryto select matched diodes as the varactor diodes 13,23,33,43, unlike the electronic tuner shown in Fig. 2. Further, an adjustmentfortracking is not required, nor are the tracking capacitors 15,25,35,45 necessitated. Hence, it is possible to widen the tuning range. However, the tuner shown in Fig. 3 suffers from the following disadvntages. First, feedback circuits ars provided to detectthesignal levels of intermediate frequencies orfor otherfunctions and so it takes a long timeforthe controller 6to adjustthetuning circuits
until the best conditions are attained.Secondly, the
levels ofthe intermediate-frequency signals are corn
pared with certain levels to adjust the tuning frequen
cies and, therefore, if the electric field strength varies
because offading orfor other cause during adjust
ment, then a normal detection is not permitted. This
may resultin a malfunction. In addition, the controller
6 needs complicated and sophisticated function and
hence it is expensive.
Inthetunershown in Fig. 1 parts similartothose in Figs. 2 and 3 are similarly referenced.
Thetunershown in Fig. has has a controller 9 which supplies digital signals to digital-to-analog converters 16,26,36,46, wherethe digital signals are converted into DC voltages. These DC voltages are supplied to varactor diodes 13,23,33,43 to separately adjustthe tuning frequencies of tuning circuits 1 to 4 so thatthey coincide with the intermediate frequencies and the local oscillatorfrequency. The digital signals delivered from the controller 9 correspond to the information regarding voltages for selecting a channel,the information being readfrom a storage device 7 in response to the selected channel.Before the electronic tuner is shipped from the factory, information about voltages for selecting each channel is stored in the storage device 7, the voltages being capable of adjusting the tuning circuits 1 and 4for resonance according to the selected channel. The tuning circuits 1 to 4 have the varactor diodes 13,23,33,43 and the inductances 11,21,31,41 which differ in characteristics. The controller9 supplies addresses to the storage device 7 according to the selected channel so that certain information on voltages for selecting a channel maybe readfrom the storagedevice 7. The controller 9then delivers digital signals to the D/Aconverters 16, 26,36,46.
In the configuration constructed as described above, certain information about voltages for selecting a channel is read from the storage device 7 according to a selection of a received channel. The tuning circuits 1 to 4 are tuned to their respective certain tuning frequencies. Accordingly, no problems are presented if the tuning circuits 1 to 4 differ in c3narecteristics.Also,traclcing is unnecessary. Further, it is not necessary to select matched varactor diodes 13,23,33,43. In addition, since tracking is not needed, tracking capacitors such as the tracking capacitors 15, 25,35,45 ofthe conventional tuner can be dispensed with. Therefore, the tuning range can be extended.
Furthermore, channels can be selected in a short time, because feedback circuits for detecting the levels of signals of intermediate frequencies are not provided.
Yet further, no malfunction takes place if the electric field intensity varies. Additionally, the controller 9 is simpler in function and cheaper accordinglythan the controller6sthown in Fig. 3.
As described thus far, in the novel electronic tuner,
DC voltages are applied to tuning circuits and a local oscillator circuit according to information concerning the DC voltages in response to a selected channel, in orderthatthe tuning frequencies ofthe tuning circuits and the frequency ofthe local oscillator circuit coincide with certain values. Therefore, neither selection of matched varactor diodes nor tracking is needed, unlike the conventional tuners. Because information aboutvoltages for selecting a channel is read frorn a storage device, and because DC voltages corresponding to the information are applied to the tuning circuits and the local oscillatorcircuit, detection ofthe levels of intermediate-frequencysignals is not
necessary. Also, any desired channel can be selected
rapidly. Further, no malfunction occurs if the electric field strength varies during tuning operation. In addition it is only necessary that information concern
ing voltages for selecting a channel be read from a storage device according to the selected channel, and thatthe DC voltages be applied to the tuning circuits
and the local oscillator circuit. The tuner is relatively
simple in function and economical to fabricate.
Claims (3)
1. An electronictunercomprising a plurality of tuning circuits each including a varactor diode, a local oscillator circuit inciuding a varactor diode, and a storage device in which information concerning voltages for selecting each channel is stored, the voltages being set for the tuning frequencies ofthe tuning circuits andforthefrequencyofthe local oscillator circuit for each channel, the voltages being applied to the tuning circuits and the local oscillator circuit, respectively, in accordance with the information which is read form the storage device according totheselected channel.
2. An electronictuneraccording to Claim 1,further comprising a controllerwhich is connected to said storage device and which is also connected to the tuning circuitsandthe local oscillatorcircuitviatheir respective digital-to-analog converters.
3. An electronic tuner substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5528686A JPS62210719A (en) | 1986-03-12 | 1986-03-12 | Electronic tuner |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8704179D0 GB8704179D0 (en) | 1987-04-01 |
| GB2187906A true GB2187906A (en) | 1987-09-16 |
Family
ID=12994338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08704179A Withdrawn GB2187906A (en) | 1986-03-12 | 1987-02-23 | Electronic tuners |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS62210719A (en) |
| DE (1) | DE3707839A1 (en) |
| GB (1) | GB2187906A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2272341A (en) * | 1992-10-21 | 1994-05-11 | Fagor S Coop Ltda | Programmable electronic tuner for collective TV aerials using analog memory |
| EP0601743A1 (en) * | 1992-12-10 | 1994-06-15 | Nokia Mobile Phones Ltd. | Tuning of a radio receiver |
| EP0629045A1 (en) * | 1993-06-07 | 1994-12-14 | MIVAR S.r.l. | Tuning device for a receiver of radioelectric signals with coils obtained by printing |
| US5925057A (en) * | 1998-01-26 | 1999-07-20 | Blomdahl Medical | Ear piercing apparatus |
| EP1794883B2 (en) † | 2004-09-27 | 2018-03-21 | Unitron | Electronic filter device for the reception of tv-signals |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2578951B2 (en) * | 1988-10-31 | 1997-02-05 | 日本電気株式会社 | Antenna tuning control circuit |
| US5905948A (en) * | 1995-07-25 | 1999-05-18 | Toko Kabushiki Kaisha | High frequency channel selecting circuit for radio receiver and method of manufacturing tuning circuits therefor |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1276815A (en) * | 1970-02-04 | 1972-06-07 | Motorola Inc | A system for selecting one of a plurality of control units for tuning a wave signal receiver |
| GB2105935A (en) * | 1981-09-16 | 1983-03-30 | Rca Corp | Television tuning system with electronic frequency adjustment apparatus |
| GB2137447A (en) * | 1983-03-28 | 1984-10-03 | Rca Corp | Rf prom tracking for tuners |
| EP0147518B1 (en) * | 1983-09-07 | 1990-10-03 | GRUNDIG E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig holländ. Stiftung & Co. KG. | Aligning method for a multistage selective amplifier and circuit arrangement for carrying it out |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2814577A1 (en) * | 1978-04-05 | 1979-10-11 | Nordmende | Radio receiver with microcomputer - generating control signals for input and main tuning circuits and controlling changeover |
| DE2834231A1 (en) * | 1978-08-04 | 1980-02-28 | Blaupunkt Werke Gmbh | Synchronisation of oscillator with input circuit of superhet receiver - sorting control voltages for input circuit corresp. to those of oscillator |
-
1986
- 1986-03-12 JP JP5528686A patent/JPS62210719A/en active Pending
-
1987
- 1987-02-23 GB GB08704179A patent/GB2187906A/en not_active Withdrawn
- 1987-03-11 DE DE19873707839 patent/DE3707839A1/en not_active Ceased
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1276815A (en) * | 1970-02-04 | 1972-06-07 | Motorola Inc | A system for selecting one of a plurality of control units for tuning a wave signal receiver |
| GB2105935A (en) * | 1981-09-16 | 1983-03-30 | Rca Corp | Television tuning system with electronic frequency adjustment apparatus |
| GB2137447A (en) * | 1983-03-28 | 1984-10-03 | Rca Corp | Rf prom tracking for tuners |
| EP0147518B1 (en) * | 1983-09-07 | 1990-10-03 | GRUNDIG E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig holländ. Stiftung & Co. KG. | Aligning method for a multistage selective amplifier and circuit arrangement for carrying it out |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2272341A (en) * | 1992-10-21 | 1994-05-11 | Fagor S Coop Ltda | Programmable electronic tuner for collective TV aerials using analog memory |
| ES2060528A1 (en) * | 1992-10-21 | 1994-11-16 | Fagor S Coop Ltda | Programmable electronic tuner for collective TV aerials using analog memory |
| GB2272341B (en) * | 1992-10-21 | 1996-09-04 | Fagor S Coop Ltda | Programmable electronic tuner for collective tv aerials |
| DE4335091C2 (en) * | 1992-10-21 | 2002-11-07 | Fagor S Coop Ltda | Programmable electronic tuner for television antennas |
| EP0601743A1 (en) * | 1992-12-10 | 1994-06-15 | Nokia Mobile Phones Ltd. | Tuning of a radio receiver |
| US5524288A (en) * | 1992-12-10 | 1996-06-04 | Nokia Mobile Phones Ltd. | Tuning of a radio receiver |
| EP0629045A1 (en) * | 1993-06-07 | 1994-12-14 | MIVAR S.r.l. | Tuning device for a receiver of radioelectric signals with coils obtained by printing |
| US5925057A (en) * | 1998-01-26 | 1999-07-20 | Blomdahl Medical | Ear piercing apparatus |
| EP1794883B2 (en) † | 2004-09-27 | 2018-03-21 | Unitron | Electronic filter device for the reception of tv-signals |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3707839A1 (en) | 1987-09-24 |
| JPS62210719A (en) | 1987-09-16 |
| GB8704179D0 (en) | 1987-04-01 |
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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) |