DE2805447A1 - TV receiver using high tuning voltage - has choke and grounding capacitor connected to UHF mixer transistor amplifying IF signal - Google Patents
TV receiver using high tuning voltage - has choke and grounding capacitor connected to UHF mixer transistor amplifying IF signalInfo
- Publication number
- DE2805447A1 DE2805447A1 DE19782805447 DE2805447A DE2805447A1 DE 2805447 A1 DE2805447 A1 DE 2805447A1 DE 19782805447 DE19782805447 DE 19782805447 DE 2805447 A DE2805447 A DE 2805447A DE 2805447 A1 DE2805447 A1 DE 2805447A1
- Authority
- DE
- Germany
- Prior art keywords
- band
- uhf
- mixer transistor
- tuning voltage
- choke
- 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- Withdrawn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
- H03J5/24—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 a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection
- H03J5/242—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 a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection
- H03J5/244—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 a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection using electronic means
Abstract
Description
Schaltungsanordnung für Fernseh-EmpfangsaggregateCircuit arrangement for television reception units
Die vorliegende Erfindung bezieht sich auf eine Schaltungsanordnung für Fernseh-Empfsngsaggregate mit hoher Abstimmspannung im Band I (Kanal 2), deren UHF-Zwischenfrequenz über einen VHF-Mischtransistor nachverstärkt wird. Bei derart aufgebauten Fernseh-Empfangsaggregaten mit einer Abstimmspannung von beispielsweise > 1,8 Volt im Band I kanal 2), tritt bei UKF-Betrieb im untersten Kanal (E 21) und einer niedrigen Abstimmspannung von ca. 0,9 Volt eine Unterdrückung der Zwischenfrequenz am VHF-Mischereingang auf, die durch die Abstimmung des Sekundärbandfilterkreises in dem Zwischenfrequenz-Bereich bedingt ist. Der Sekundärbandfilterkreis muß derart verstimmt werden, daß er außerhalb des Zwischenfrequenz-Bereichs liegt und im UHF-Betrieb nicht stört. Dies wird mit der Bandumschaltdiode für Band I/III dieses Sekundärbandfilterkreises vorgenommen. Bei UHF-Betrieb wird die Bandumschaltdiode nach Band III umgeschaltet. Dabei darf im Band I-Betrieb die Umschaltung die negative Vorspannung auf der Band III-Leitung nicht bedämpfen.The present invention relates to a circuit arrangement for television receivers with high tuning voltage in band I (channel 2), their UHF intermediate frequency is amplified via a VHF mixer transistor. With such built television reception units with a tuning voltage of, for example > 1.8 volts in band I channel 2), occurs in UKF operation in the lowest channel (E 21) and a low tuning voltage of approx. 0.9 volts, a suppression of the intermediate frequency at the VHF mixer input, which is achieved by tuning the secondary band filter circuit is conditional in the intermediate frequency range. The secondary band filter circuit must be such be detuned that it is outside the intermediate frequency range and in UHF mode not bother. This is done with the band switching diode for band I / III of this secondary band filter circuit performed. In UHF operation, the band switching diode is switched to band III. In this case, in band I operation, the switchover may reduce the negative bias voltage on the band Do not attenuate III line.
Bei einer bekannten Schaltanordnung für Fernseh-Empfangsaggregate dieser Art ist ein hochohmiger Widerstand von UHF-Schaltleitung auf die Band III-Leitung angeordnet, welcher im UHF-Betrieb den Sekundärkreis des VRF-Bandfilters nach Band III verstimmt und im Band 1-Betrieb die Band III-Leitung wenig bedämpft, Diese Schaltungsanordnung weist jedoch den Nachteil auf, daß eine Anschwinggefahr des Band III-Oszillators im UHF-Betrieb besteht und eine Bedämpfung der Band III-Leitung im Band I-Betrieb erfolgt.In a known switching arrangement for television reception units this type is a high resistance from the UHF switching line to the band III line arranged, which in UHF operation the secondary circuit of the VRF band filter by band III out of tune and in band 1 operation the band III line is slightly attenuated, this circuit arrangement however, has the disadvantage that there is a risk of the band III oscillator starting to oscillate in UHF operation and an attenuation of the band III line in band I operation he follows.
Der Erfindung liegt die Aufgabe zugrunde, eine Schaltanordnung für Fernseh-Empfangsaggregate mit hoher Abstimmspannung im Band I (Kanal 2) zu entwickeln, die die aufgezeigten Nachteile vermeidet Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß der Kollektorstrom des UHF-Nischtransistors durch Anordnung eines ibblockkondensators hochfrequenzseitig am Ftißpunkt des Zwischenfrequenz-Bandfilters gegen Masse geführt ist und daß der Kollektorstrom des UEF-Mischtransistors gleichstromseitig über eine Hochfrequenz-Drossel an die Anode der Sekundärkreis-Schaltdiode im THF-Bandfilter gelegt wird0 Durch diese Maßnahme schaltet der Kollektorstrom die Sekundär-Schaltkreisdiode im UHF-Betrieb nach Band III und im Band I-Betrieb ist der Kollektor des dann abgeschalteten UHF-Mischtransistors für die negative Vorspannung auf der Band III-Leitung extrem hochohmig, so daß keine Bedämpfung eintreten kann.The invention is based on the object of a switching arrangement for To develop television reception sets with high tuning voltage in band I (channel 2), which avoids the disadvantages indicated. This object is achieved according to the invention solved that the collector current of the UHF niche transistor by arranging an ibblockkondensators On the high-frequency side, at the Ftißpunkt of the intermediate frequency band filter led to ground is and that the collector current of the UEF mixer transistor on the DC side via a High-frequency choke to the anode of the secondary circuit switching diode in the THF band filter 0 With this measure, the collector current switches the secondary circuit diode In UHF operation according to Volume III and in Band I operation, the collector of the then switched off UHF mixer transistor for the negative bias on the Band III line extreme high resistance, so that no attenuation can occur.
Die vorteilhaften Einzelheiten der Erfindung sind nachfolgend anhand eines in der Zeichnung veranschaulichten Ausführungsbeispiels beschrieben.The advantageous details of the invention are based on the following of an embodiment illustrated in the drawing.
Die Schaltung gemäß Figur 1 zeigt zwei HF-Mischstufen mit dem zugehörigen HF-Bandfilter-Ausgangskreisen. Dabei wird vorzugsweise die Mischstufe bestehend aus dem Transistor 7, dem Emitterwiderstand 5, dem Basisspannungsteiler6, 9, dem Basisabblockkondensator 8 und dem Zwischenfrequenzbandfilter 10, 11, 12, 13, 14, 15, 16 zusammen mit dem Bandfilterkreis 1, 2, 3, 4 für UHF, die Mischstufe bestehend aus dem Transistor 37, dem Emitterwiderstand 29, dem Basisspannungsteiler30, 32, dem Basisabblockkondensator 31 nach dem ZF-Bandfilter 33, 34, 35, 36 zusammen mit den über die Diode 26 und 27, 28 umschaltbaren Eingangskreisen aus 19, 20, 21, 25 bzw.The circuit according to FIG. 1 shows two RF mixer stages with the associated one RF band filter output circuits. In this case, the mixing stage is preferably composed from the transistor 7, the emitter resistor 5, the base voltage divider 6, 9, the Base blocking capacitor 8 and the intermediate frequency band filter 10, 11, 12, 13, 14, 15, 16 together with the band filter circuit 1, 2, 3, 4 for UHF, consisting of the mixer stage from the transistor 37, the emitter resistor 29, the base voltage divider 30, 32, the base blocking capacitor 31 after the IF bandpass filter 33, 34, 35, 36 together with the input circuits from 19, 20, 21, 25 which can be switched via the diode 26 and 27, 28 respectively.
19, 20, 21, 22, 23, 24 vorzugsweise für die VHF-Bereiche Band III und Band I verwendet. Im UHF-Betrieb wird über den Kollektorstrom des Transistors 7 die Diode 26 durchgeschaltet und damit der Sekundärkreis des Bandfilters für VHF 20, 21, 22, 23, 24, 25 auf Band III Betrieb umgeschaltet. Somit kann nicht der erfindungsgemäß zu verhindernde Effekt auftreten, daß der normalerweise auf Band I geschaltete Sekundärkreis bei niedrigen UD-Werten auf die Zwischenfrequenz abgestimmt wird und die UHF-Zwischenfrequenz unterdrückt, Im Band I Bet b ist der Kollektorkreis des abgeschalteten UHF-Mischtransistors 7 gleichstrommäßig sehr hochohmig, so daß keine Bedämpfung der hochohmigen negativen Vorspannung am Kondensator 27 zur Sperrung an der Diode 26 auftreten kann.19, 20, 21, 22, 23, 24 preferably for the VHF areas Band III and Volume I. In UHF mode, the transistor's collector current is used 7 the diode 26 is switched through and thus the secondary circuit of the band filter for VHF 20, 21, 22, 23, 24, 25 switched to band III operation. Thus, the invention cannot The effect to be prevented from occurring is that the secondary circuit, which is normally switched to band I. at low UD values it is tuned to the intermediate frequency and the UHF intermediate frequency suppressed, in band I Bet b is the collector circuit of the switched off UHF mixer transistor 7 very high resistance in terms of direct current, so that no attenuation of the high resistance negative Bias voltage on the capacitor 27 to block the diode 26 can occur.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782805447 DE2805447A1 (en) | 1978-02-09 | 1978-02-09 | TV receiver using high tuning voltage - has choke and grounding capacitor connected to UHF mixer transistor amplifying IF signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782805447 DE2805447A1 (en) | 1978-02-09 | 1978-02-09 | TV receiver using high tuning voltage - has choke and grounding capacitor connected to UHF mixer transistor amplifying IF signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE2805447A1 true DE2805447A1 (en) | 1979-08-16 |
Family
ID=6031532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DE19782805447 Withdrawn DE2805447A1 (en) | 1978-02-09 | 1978-02-09 | TV receiver using high tuning voltage - has choke and grounding capacitor connected to UHF mixer transistor amplifying IF signal |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE2805447A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4577171A (en) * | 1983-05-11 | 1986-03-18 | Telefunken Electronic Gmbh | Input circuit comprising at least two input paths |
| EP0277692A2 (en) * | 1987-02-05 | 1988-08-10 | Philips Patentverwaltung GmbH | Combined IF absorption and parallel circuit for a TV tuner |
-
1978
- 1978-02-09 DE DE19782805447 patent/DE2805447A1/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4577171A (en) * | 1983-05-11 | 1986-03-18 | Telefunken Electronic Gmbh | Input circuit comprising at least two input paths |
| EP0277692A2 (en) * | 1987-02-05 | 1988-08-10 | Philips Patentverwaltung GmbH | Combined IF absorption and parallel circuit for a TV tuner |
| EP0277692A3 (en) * | 1987-02-05 | 1989-12-06 | Philips Patentverwaltung GmbH | Combined if absorption and parallel circuit for a tv tuner |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 8120 | Willingness to grant licences paragraph 23 | ||
| 8127 | New person/name/address of the applicant |
Owner name: TELEFUNKEN ELECTRONIC GMBH, 7100 HEILBRONN, DE |
|
| 8110 | Request for examination paragraph 44 | ||
| 8139 | Disposal/non-payment of the annual fee |