DE1766682B1 - Self-oscillating mixer for the UHF range - Google Patents

Self-oscillating mixer for the UHF range

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Publication number
DE1766682B1
DE1766682B1 DE19681766682D DE1766682DA DE1766682B1 DE 1766682 B1 DE1766682 B1 DE 1766682B1 DE 19681766682 D DE19681766682 D DE 19681766682D DE 1766682D A DE1766682D A DE 1766682DA DE 1766682 B1 DE1766682 B1 DE 1766682B1
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Germany
Prior art keywords
circuit
capacitor
mixer
inductance
transistor
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Granted
Application number
DE19681766682D
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German (de)
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DE1766682C2 (en
Inventor
Lehmann Heinz Guenter
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Philips Intellectual Property and Standards GmbH
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Philips Patentverwaltung GmbH
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Publication of DE1766682B1 publication Critical patent/DE1766682B1/en
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Publication of DE1766682C2 publication Critical patent/DE1766682C2/en
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/02—Details
    • H03J3/16—Tuning without displacement of reactive element, e.g. by varying permeability
    • H03J3/18—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance
    • H03J3/185—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance with varactors, i.e. voltage variable reactive diodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1203—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier being a single transistor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1231—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier comprising one or more bipolar transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1237—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device comprising means for varying the frequency of the generator
    • H03B5/124—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device comprising means for varying the frequency of the generator the means comprising a voltage dependent capacitance
    • H03B5/1243—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device comprising means for varying the frequency of the generator the means comprising a voltage dependent capacitance the means comprising voltage variable capacitance diodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1237—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device comprising means for varying the frequency of the generator
    • H03B5/1256—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device comprising means for varying the frequency of the generator the means comprising a variable inductance
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1296—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the feedback circuit comprising a transformer
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D9/00—Demodulation or transference of modulation of modulated electromagnetic waves
    • H03D9/06—Transference of modulation using distributed inductance and capacitance
    • H03D9/0658—Transference of modulation using distributed inductance and capacitance by means of semiconductor devices having more than two electrodes
    • H03D9/0666—Transference of modulation using distributed inductance and capacitance by means of semiconductor devices having more than two electrodes using bipolar transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
    • H03B5/1805—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a coaxial resonator

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Superheterodyne Receivers (AREA)

Description

Bei der Erfindung wird ausgegangen von einer selbstschwingenden Mischstufe für den UHF-Bereich mit einem in Basisschaltung betriebenen Mischtransistor, dessen Kollektorkreis die Serienschaltung einer Kapazitätsdiode und eines Festkondensators enthält, der ferner die über dem Festkondensator erzeugte Spannung über einen Rückkopplungskondensator zum Emitter zurückgeführt wird und die ZF-Signale über ein Bandfilter entnommen werden. Derartige Mischstufen werden insbesondere in Fernsehempfängern zum Empfang ,der Bereiche IV und V (470 bis 790 MHz) benutzt (deutsche Auslegeschrift 1251820).The invention is based on a self-oscillating mixer stage for the UHF range with a mixed transistor operated in a basic circuit, its Collector circuit the series connection of a capacitance diode and a fixed capacitor which further includes the voltage generated across the fixed capacitor via a feedback capacitor is fed back to the emitter and the IF signals are taken through a band filter will. Such mixer stages are used in particular in television receivers for reception , which uses ranges IV and V (470 to 790 MHz) (German Auslegeschrift 1251820).

Durch die stark abnehmende Güte der Kapazitätsdiode zum niederfrequenten Bereichsende hin werden die Schwingbedingungen für den Oszillator dort sehr ungünstig, obgleich die Steilheit und die Kapazität der Kapazitätsdiode dort am größten ist, so daß durch das Teilerverhältnis Diode-Festkondensator am Festkondensator die größtmögliche Spannung abgenommen und über den Rückkopplungskondensator dem Emitter zugeführt wird. Ein größerer Rückkopplungskondensator verbessert zwar die Schwingbedingungen am unteren Bereichsende, dafür treten aber Schwierigkeiten auf durch Einengung der Frequenzvariation und durch unstabilen Schwingzustand in der oberen Hälfte des Frequenzbereichs.Due to the strongly decreasing quality of the capacitance diode to the low frequency Towards the end of the range, the oscillation conditions for the oscillator become very unfavorable there, although the steepness and the capacitance of the capacitance diode is greatest there, so that through the divider ratio diode-fixed capacitor at the fixed capacitor the greatest possible Voltage is removed and fed to the emitter via the feedback capacitor will. A larger feedback capacitor improves the oscillation conditions at the lower end of the range, but difficulties arise due to the narrowing of the Frequency variation and unstable vibration condition in the upper half of the frequency range.

Es ist bereits eine Schaltung mit einer zusätzlichen induktiven Rückkopplung vom Ausgang auf den Eingang bekannt. Durch die zusätzliche Rückkopplung soll ein besseres und gleichmäßigeres Schwingverhalten über den gesamten Frequenzbereich erreicht werden. Die induktive Rückkopplung erfordert aber einen zusätzlichen Abgleichvorgang, um die Schwingung des Oszillators über den ganzen Durchstimmbereich richtig einzustellen.It is already a circuit with an additional inductive feedback known from the exit to the entrance. The additional feedback should be a better and more even vibration behavior over the entire frequency range can be achieved. However, the inductive feedback requires an additional adjustment process, to set the oscillation of the oscillator correctly over the entire tuning range.

Die Aufgabe besteht darin, ein besseres und gleichmäßigeres Schwingverhalten ohne zusätzliche Rückkopplung zu erzielen. Diese Aufgabe wird durch die im Anspruch 1 angegebene Erfindung gelöst. Vorteilhafte Weiterbildungen der Erfindungen sind in den Unteransprüchen beschrieben. Bei Ausbildung der Mischstufe nach Anspruch 2 kann die Oszillatorfrequenz in unmittelbarer Nähe des unteren Bereichsendes beeinffußt werden, so daß Gleichlauffehler zwischen dem Oszillatorkreis einerseits und den beiden UHF-Bandfilterkreisen der Vorstufe andererseits korrigiert werden.The task is to achieve a better and more even vibration behavior without additional feedback. This task is carried out by the in claim 1 specified invention solved. Advantageous further developments of the inventions are described in the subclaims. When forming the mixing stage according to claim 2 can influence the oscillator frequency in the immediate vicinity of the lower end of the range be, so that synchronization errors between the oscillator circuit on the one hand and the both UHF band filter circuits of the preamp can be corrected on the other hand.

Ein Ausführungsbeispiel der Erfindung wird an Hand der Zeichnung näher erläutert.An embodiment of the invention is explained in more detail with reference to the drawing explained.

Die Zeichnung zeigt die selbstschwingende Mischstufe einer Fernsehempfängerschaltung für .den Bereich von 470 bis 790 MHz. Der Gleichstromarbeitspunkt des Mischstufentransistors T ist durch den Basisspannungsteiler aus den Widerständen R1 und Rz sowie durch den Emitterwiderstand R3 vorgegeben. Die Basis des Transistors T liegt über einem Kondensator Cl von 1000 pF an Masse, so .daß der Transistor T für die in Betracht kommenden Schwingungen in Basisschaltung betrieben wird. Der Kollektor des Transistors T ist über einen Kondensator C., von 3,9 pF mit einer Induktivität L1 verbunden, deren anderes Ende geerdet ist.The drawing shows the self-oscillating mixer stage of a television receiver circuit for the range from 470 to 790 MHz. The DC operating point of the mixer transistor T is through the base voltage divider from the resistors R1 and Rz as well as through the emitter resistor R3 specified. The base of the transistor T is above one Capacitor Cl of 1000 pF to ground, so .that the transistor T for the into consideration coming vibrations is operated in the basic circuit. The collector of the transistor T is connected to an inductance L1 via a capacitor C., 3.9 pF, the other end of which is grounded.

Die Induktivität L1 wird durch ein Leitungsstück gebildet, das mit der Basis eines U-förmig gebogenen, geerdeten Blechstreifens verlötet ist und das parallel zu dessen Schenkeln verläuft, so daß eine Kammer K1 entsteht. Damit die Induktivität auf den erforderlichen Wert abgeglichen werden kann, ist ein kurzgeschlossener Drahtbügel L,' im Inneren der Kammer angelötet. Die Größe der Induktivität Ll hängt daher von der magnetischen Kopplung zwischen L1 und L1 und damit von der Lage von L1' ab und kann durch Verbiegen des Drahtbügels L1 auf den gewünschten Wert gebracht werden.The inductance L1 is formed by a piece of line that is with the base of a U-shaped bent, earthed sheet metal strip is soldered and that runs parallel to its legs, so that a chamber K1 is formed. So that Inductance can be trimmed to the required value is a short-circuited Wire bracket L, 'soldered inside the chamber. The size of the inductance Ll depends hence from the magnetic coupling between L1 and L1 and thus from the position of L1 'and can be brought to the desired value by bending the wire bracket L1 will.

Parallel zur Induktivität L1 ist die Serienschaltung einer Kapazitätsdiode Dl vom Typ BB 105 und eines Festkondensators C3 von 15 pF geschaltet, wobei der Festkondensator an der einen Seite geerdet und an der anderen Seite über einen Rückkopplungskondensator C4 von 1,2 pF mit dem Emitter des Mischstufentransistors verbunden ist. Es erregen sich daher Schwingungen, deren Frequenz etwa mit der (Parallel-) Resonanzfrequenz des Ausgangskreises C3, Dl, L1 übereinstimmt. Die Parallelresonanzfrequenz wird ihrerseits durch die Vorspannung der Kapazitätsdiode Dl bestimmt, .die dieser am Verbindungspunkt mit den Kondensatoren. C. und Ca über den Widerstand R4 zugeführt wird.The series connection of a capacitance diode is parallel to the inductance L1 Dl of the type BB 105 and a fixed capacitor C3 of 15 pF connected, the Fixed capacitor grounded on one side and via a feedback capacitor on the other C4 of 1.2 pF is connected to the emitter of the mixer transistor. Excite it therefore vibrations, their frequency roughly with the (parallel) resonance frequency of the output circuit C3, Dl, L1 matches. The parallel resonance frequency becomes in turn determined by the bias of the capacitance diode Dl, .the this on Connection point with the capacitors. C. and Ca supplied through resistor R4 will.

Für Wechselstrom liegt der Basis-Emitter-Diode ein Kondensator C, parallel, der den induktiven Eingangswiderstand und damit auch die Rückkopplung etwas vergrößert und damit die Rückkopplungsbedingungen am niederfrequenten Bereichsende verbessert. Dieser Kondensator muß aber verhältnismäßig klein bemessen sein, damit keine Einengung der Abstimmvariation oder bei den höheren Frequenzen kein unstabiler Schwingzustand auftritt. Ein geeigneter Wert für C5 ist 1 pF.For alternating current, the base-emitter diode has a capacitor C, parallel, the inductive input resistance and thus also the feedback slightly increased and thus the feedback conditions at the low-frequency range end improved. This capacitor must be sized relatively small so that no narrowing of the tuning variation or, at the higher frequencies, no unstable one Vibration condition occurs. A suitable value for C5 is 1 pF.

Außerdem ist zwischen den Emitter und den Emitterwiderstand R3 eine Koppelschleife L2 geschaltet, die die Mischstufe an die vorhergehende Vorstufe ankoppelt, von der in der Zeichnung nur die Spule L2 und die Kapazitätsdiode D, dargestellt sind. Die Spule L_, hat einen ähnlichen Aufbau wie die die Spule L1, und die Koppelschleife L.' ragt in die die Spule L, umgebende Kammer K, hinein. Der Verbindungspunkt der Koppelschleife L.' und des Emitterwiderstandes R3 ist über die Serienschaltung an der Induktivität L3, die mit den anderen Spulen magnetisch nicht gekoppelt ist, und eines Kondensators C, von 100 pF mit Erde verbunden. Dadurch, daß der Verbindungspunkt nicht direkt über den Kondensator, sondern unter Zwischenschaltung der Induktivität L, geerdet ist und somit die Gesamtinduktivität parallel zum Eingang der Mischstufe größer ist, wird erreicht, daß insbesondere bei niedrigen Frequenzen die Schwingungen des Oszillators in diesem Bereich aufrechterhalten werden können. Die Bemessung der Spule L3 ist ein Kompromiß zwischen einem guten Schwingverhalten am unteren Bereichsende einerseits und der Anpassung der Mischstufe an die Vorstufe am oberen Bereichsende andererseits.In addition, between the emitter and the emitter resistor R3 is a Coupling loop L2 switched, which couples the mixer to the previous pre-stage, of which only the coil L2 and the capacitance diode D are shown in the drawing are. The coil L_, has a similar structure to that of the coil L1, and the coupling loop L. ' protrudes into the chamber K surrounding the coil L. The connection point of the Coupling loop L. ' and the emitter resistor R3 is on via the series circuit the inductance L3, which is not magnetically coupled to the other coils, and a capacitor C, 100 pF connected to ground. By being the connection point not directly via the capacitor, but with the interposition of the inductance L, is grounded and thus the total inductance parallel to the input of the mixer is greater, it is achieved that the vibrations, especially at low frequencies of the oscillator can be maintained in this range. The dimensioning the coil L3 is a compromise between good oscillation behavior at the bottom End of range on the one hand and the adaptation of the mixer to the pre-stage at the top End of range on the other hand.

Die Induktivität L3 wäre nicht erforderlich, wenn die Induktivität der Koppelschleife L.' genügend groß wäre. Da die Koppelschleife aber so bemessen werden muß, daß eine optimale Anpassung zwischen der Vorstufe und der Mischstufe erzielt wird, kann sie nur vergrößert werden, wenn gleichzeitig die magnetische Kopplung mit der Spule L, der Vorstufe verringert wird. Das würde aber bedeuten, daß die Koppelschleife länger sein (=größere Induktivität) und von der Spule L, einen größeren Abstand (= kleinere Kopplung) haben müßte, so daß sie nicht mehr in die Kammer passen würde.The inductance L3 would not be required if the inductance the coupling loop L. ' would be big enough. Since the coupling loop is so dimensioned must be that an optimal match between the pre-stage and the mixer stage is achieved, it can only be increased if at the same time the magnetic Coupling with the coil L, the pre-stage is reduced. But that would mean that the coupling loop be longer (= greater inductance) and from the coil L, a greater distance (= smaller coupling) should have so that it would no longer fit in the chamber.

Die Zwischenfrequenzsignale werden der Mischstufe über ein Bandfilter (BF) entnommen, das an einen an der einen Seite geerdeten und an der anderen Seite über eine Spule L4 mit dem Kollektor des Mischstufentransistors verbundenen Kondensator C7 von .1,7 pF angeschlossen ist. Dieser Kondensator und der Kondensator C., sind die Kapazität des Primärkreises des Bandfilters.The intermediate frequency signals are sent to the mixer via a band filter (BF), one earthed on one side and one earthed on the other Capacitor connected to the collector of the mixer transistor via a coil L4 C7 of .1.7 pF is connected. This capacitor and capacitor C., are the capacity of the primary circuit of the band filter.

Die Spule L, ist so bemessen, daß sie einerseits zusammen mit. den Kondensatoren C.= und C; einen Hilfskreis -eringer Güte (rund 20) bildet, der bei einer Frequenz dicht unterhalb der niedrigsten UHF-Empfangsfrequenz. etwa bei -450 MHz, in Parallelresonanz ist (die Induktivität L1 kann in diesem Frequenzbereich vernachlässigt werden), andererseits aber für die Zwischenfrequenz einen vernachlässigbar kleinen induktiven Widerstand darstellt.The coil L is dimensioned so that it is on the one hand together with. the Capacitors C. = and C; forms a low-quality auxiliary group (around 20) that is part of a frequency just below the lowest UHF reception frequency. around -450 MHz, is in parallel resonance (the inductance L1 can in this frequency range can be neglected), but on the other hand one is negligible for the intermediate frequency represents small inductive resistance.

Dadurch wird die Verstärkung in unserem Frequenzbereich im Vergleich zu der Verstärkung am oberen Bereichsende angehoben, so daß das Schwin5 verhalten über den gesamten Frequenzbereich annähernd gleichbleibt.This will compare the gain in our frequency range raised to the reinforcement at the upper end of the range, so that the Schwin5 behave remains approximately the same over the entire frequency range.

Wird die Induktivität des Hilfskreises (L4) veränderlich gestaltet, so hat man ein sehr wirksames Mittel, um die Oszillatorfrequenz am unteren Bereichsende zu beeinflussen, was oft erforderlich ist, um Gleichlauffehler zwischen dem Oszillator einerseits und den UHF-Bandfilterkreisen andererseits, verursacht durch Streuungen der Kennlinien der Kapazitätsdioden oder anderer frequenzbestimmender Schaltelemente, zu korrigieren.If the inductance of the auxiliary circuit (L4) is made variable, this is a very effective way of keeping the oscillator frequency at the lower end of the range to influence what is often required to avoid synchronization errors between the oscillator on the one hand and the UHF band filter circuits on the other hand, caused by scattering the characteristics of the capacitance diodes or other frequency-determining switching elements, to correct.

Claims (3)

Patentansprüche: 1. Selbstschwingende Mischstufe für den UHF-Bereich mit einem in Basisschaltung betriebenen Mischtransistor, dessen Kollektorkreis die Serienschaltung einer Kapazitätsdiode und eines Festkondensators enthält, bei der ferner die über dem Festkondensator erzeugte Spannung über einen Rückkopplungskondensator zum Emitter zurückgeführt wird und die ZF-Signale über ein Bandfilter entnommen werden, d a d u r c h g e k e n n -z e i c h n e t, daß das Bandfilter (BF) an einem zwischen Kollektor und Erde geschalteten Hilfskreis (L" C_) angeschlossen ist, der zusammen mit den übrigen Elementen des Ausgangskreises (C." L1) bei einer Frequenz etwas unter der untersten Empfangsfrequenz in Parallelresonanz ist. Claims: 1. Self-oscillating mixer stage for the UHF range with a mixer transistor operated in a base circuit, the collector circuit of which contains the series connection of a capacitance diode and a fixed capacitor, in which the voltage generated across the fixed capacitor is also fed back to the emitter via a feedback capacitor and the IF signals be taken through a band filter, characterized in that the band filter (BF) is connected to an auxiliary circuit (L " C_) connected between collector and earth, which together with the other elements of the output circuit (C." L1) at a frequency somewhat is in parallel resonance below the lowest receiving frequency. 2. Mischstufe nach Anspruch 1, dadurch gekennzeichnet, daß die Induktivität der Hilfskreisspule (L4) veränderlich ist. 2. Mixer according to claim 1, characterized in that the inductance the auxiliary circuit coil (L4) is variable. 3. Mischstufe nach Anspruch 1, dadurch gekennzeichnet, daß parallel zum Eingang des Mischtransistors (T) ein Kondensator (C@) geschaltet ist, dessen Blindwiderstand auch bei der höchsten Oszillatorfrequenz größer ist als der Eingangswiderstand des Mischtransistors. Mischstufe nach einem der vorhergehenden Ansprüche, die zur Ankopplung an eine Vorstufe eine im Emitterkreis des Mischtransistors wirksame Koppelschleife (L.,') enthält, dadurch gekennzeichnet, daß das eine Ende der Koppelschleife über die Serienschaltung einer Induktivität (L.) und eines Kondensators (C") geerdet ist.3. Mixing stage according to claim 1, characterized characterized in that a capacitor is parallel to the input of the mixer transistor (T) (C @) is switched, its reactance also at the highest oscillator frequency is greater than the input resistance of the mixer transistor. Mixing stage after one of the preceding claims, one in the emitter circuit for coupling to a preliminary stage of the mixing transistor contains effective coupling loop (L., '), characterized in that that one end of the coupling loop via the series circuit of an inductance (L.) and a capacitor (C ") is grounded.
DE1766682A 1968-07-03 1968-07-03 Self-oscillating mixer for the UHF range Expired DE1766682C2 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1766682 1968-07-03

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DE1766682B1 true DE1766682B1 (en) 1970-04-30
DE1766682C2 DE1766682C2 (en) 1974-04-04

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1251820B (en) * 1965-05-31

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1251820B (en) * 1965-05-31

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DE1766682C2 (en) 1974-04-04

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