DE1302946B - - Google Patents

Description

-O On

© Int. Cl .: H 03 b

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE ΛλΒ " ⁷ / ^

German class: 21 a4, 13

21 a4, 8/01

Interpretation document 1 302 946

© File number: P 13 02 946.4-35

(g) Filing date: September 30 , 1959

@ Disclosure date: -

© Day on display: February 25, 1971

Exhibition priority: -

@) Union priority

(g) Date: -

<h) Country: -

@ File number: -

@ Designation: Multi-stage oscillator with in the feedback path

horizontal actuator

@ Addition to: -

@ Elimination from: -

@ Applicant: Siemens AG, 1000 Berlin and 8000 Munich

Representative: -

Named as inventor: Vollnhals, Friedemann, Dipl.-Ing., 8190 Wolfratshausen;

Knapp, Klaus, Dipl.-Ing., 8000 Munich

Publications taken into consideration for assessing patentability: DT-PS 1 015 070 "NTZ", Issue 4/1957 , p. 195 bis

DT-AS 1 023 090 "Proceedings of the IRE",

U.S. Patent 2,444,349 February 1954, pp. 391 to

^ © 2.71 109509/93

The invention relates to a multi-stage, with a quartz oscillator as a frequency-selective member provided oscillator with an actuator located in the feedback path, which is dependent on one of the output voltage proportional DC voltage is controlled as a manipulated variable.

From the German patent 1 015 070 a circuit arrangement of a generator with a stabilized and monitored amplitude of the output voltage is known at which only the feedback loop is performed via the frequency-selective member, while the control loop of this frequency-selective member bypasses.

However, this difference compared to the oscillator mentioned at the beginning is with regard to the Desired freedom from distortion with high stability of the output voltage at the same time is essential, because with the known circuit arrangement distortion-free is only achieved if all individual assemblies are designed for a high degree of freedom from distortion.

In the circuit arrangement according to FIG. 2 of U.S. Patent 2,444,349 is admittedly by Type of circuit in which the frequency-selective element represented by a quartz is directly on the Output of the oscillator arrangement is switched on, a high level of freedom from distortion is achieved, but can with this Type of circuit under no circumstances can high output powers be achieved, since the entire output power over the quartz has to be led, which, however, already at a few milliwatts of output power due to the excessively high thermal stress would be destroyed.

In the reference "Proceedings of the IRE", February 1954, pp 391 to 401, there are also stabilization circuits for transistor oscillators where the output voltage is in the control loop compared with a reference voltage and the differential voltage to control the base current the transistors arranged in the emitter circuit serves to the frequency-determining parallel resonance circuits are connected from concentrated switching elements. It is also known to use the reference voltage in one with a thermistor for temperature compensation provided circuit to generate.

The object of the present invention is to provide an oscillator circuit arrangement of the type mentioned in the opening paragraph Art to create an optimal solution between low distortion, low quartz load, stability the output voltage against changes in load and achievable output power is achieved.

The multi-stage oscillator is designed according to the invention such that the quartz crystal as Actuator a transistor in emitter circuit is connected upstream, whose gain by changing the Base bias is changeable that an associated controller is located between the oscillator output and the actuator is located that, in addition, a push-pull output stage equipped with a push-pull output stage in front of this output Amplifier is inserted as a connection of frequency-selective element and actuator and that the output voltage taken from the amplifier in the regulator after rectification with a short time constant compared with a nominal voltage generated by a circuit arrangement with a Zener diode is and the resulting differential voltage is fed to the actuator as a manipulated variable and that A voltage divider is parallel to the Zener diode, one part of which consists of an NTC thermistor.

These measures have the advantage that

that the frequency constancy of the oscillator is only determined by the constancy of the crystal. ^{Frequency accuracies of 2 · IO -5} and more can therefore be achieved in a simple manner.
Another major advantage of such a structure compared to known arrangements is that the output voltage is distortion-free without additional filter expenditure. Furthermore, the resonance resistance of the frequency-selective element in

ίο large limits fluctuate without changing the output voltage and / or oscillator frequency. The output voltage is also independent of fluctuations in the gain of the transistors used caused by aging and / or temperature influences. It is still independent of fluctuations in the supply voltage and independent of changes in load. The arrangement also has the advantage that it enables a large control range in both directions.

zo light without overloading the quartz.

Compared to the arrangement according to the German Patent 1 015 070, the subject of the Invention has the further advantage that the frequency-selective member consisting of a quartz at the same time is used as a steep band filter, so that only the output amplifier must be designed so that its own distortion is low, while with regard to the distortion factor in the other assemblies none Needs to be taken into account.

The invention is illustrated by means of the basic flow of FIG. 1 and that shown in FIG Embodiment explained in more detail.

The requirement for high output voltage constancy (change <l%), regardless of load, Battery voltage and temperature fluctuations (including aging and tolerance of the components) with simultaneous low distortion (<0.5%) prepares for the design of generator circuits usually considerable difficulties. As a rule, only the requirement for constant voltage or low distortion can simply be met. Will If both requirements are raised, the implementation is only possible with previously known circuit arrangements possible by accepting greatly increased effort. In contrast, the circuit arrangement allows according to the invention to meet both requirements with little effort.

The basic current flow is shown in FIG. 1 shown. The feedback path for generating the oscillation amplitude runs via the amplifier VI, the frequency-determining element / and a controllable damping or amplifying element as the actuator St. The actuator St can form a unit with the amplifier V 1 and has a basic position such that the oscillation conditions are reliably met. In an oscillating state, the output voltage U _u is also available at the output of the amplifier VI . By comparison _of V with the reference value in the controller Re an actuating voltage that regulates by varying the damping of the actuator in the feedback path, the oscillation amplitude, the output voltage U _a coincides with the target value is produced on deviation from U _a the target value. The output voltage is therefore kept constant regardless of the changes within the circuit and of the external load, including changes in the mains voltage, while the magnitude of the oscillation amplitude U _i, on the other hand, is dependent on the aforementioned changes. Loading

Claims (1)

If the actuator St has sufficient backward damping, the output voltage can be regulated with very short time constants. Additional distortion products at the amplifier output are not generated because the frequency-determining element, which is represented by a quartz in series resonance circuit, acts as a bandstop filter for all frequencies (harmonics) except for the resonance frequency (fundamental wave). Due to the special properties of the circuit, quartz crystals with almost any resonance resistance can be used without changing the operating properties. The quartz load always remains small. In FIG. 2 shows the complete circuit of an oscillator with the features of the invention. Amplifier V1 and actuator St of the basic circuit diagram according to FIG. 1 are implemented by transistor T1 , the gain of which can be regulated by changing the base-emitter bias voltage. The frequency-determining element is the quartz crystal Q in series resonance circuit. The transistors T 2, Γ 3 and T 4 together result in the amplifier V 2. The output stage is designed as a push-pull circuit in order to be able to meet the required distortion damping. The feedback path runs from the emitter of transistor T 3 via resistor R 12 back to the base of transistor Tl. To keep the output voltage constant, a small part of it is tapped via winding III of output transformer V ₁ , rectified by means of the rectifier and smoothing circuit and with the Zener voltage of the Silicon diode SD compared. The DifIerenzspannung provides the base bias to the transistor Tl. The allocation is such that in the absence of the transistor Tl from output voltage maximum encryption has strengthening. The build-up safety is greater than ten times for quartz resonance resistors of 1. . . 200 kQ. The quartz current for this also remains with load changes at U _a between idling and full load always < 20 μΑ. The output voltage can be changed with the aid of the potentiometer P1. The slight change in the output voltage caused by the temperature dependence of the Zener diode SD can be compensated for by connecting a voltage divider in parallel, one part of which consists of a thermistor R21 , the other part of this voltage divider being represented by the potentiometer P1 . Claim: Multi-stage oscillator provided with a quartz oscillator as a frequency-selective element with an actuator located in the feedback path, which is controlled as a manipulated variable as a function of a direct voltage proportional to the output voltage, characterized in that a transistor (Γ1) in an emitter circuit is connected upstream of the quartz oscillator as an actuator, the amplification of which is through Change of the base bias is changeable, that an associated controller is located between the oscillator output and the actuator, that an amplifier (V2) equipped with a push-pull output stage (Γ3, T4) is inserted as a connection between the frequency-selective element and actuator and that the the amplifier {V2) taken, constant output voltage in the regulator after rectification with a short time constant is compared with a setpoint voltage generated by a circuit arrangement with a Zener diode (SD) and the resulting difference voltage to the actuator as S tell size is supplied and that a voltage divider is parallel to the Zener diode, one part of which consists of a thermistor {R 21). 1 sheet of drawings