SU1109854A1 - Frequency-controlled crystal oscillator - Google Patents

Abstract

A FREQUENCY-CONTROLLED QUARTZ GENERATOR containing a transistor, the emitter of which through the first resistor is connected to the power bus, the inductor, the "first output of which is connected to the collector of the transistor, and the second through a parallel-connected second resistor and the first blocking capacitor to the common bus, resistive divider, which is connected between the second output of the inductor and the supply bus, and its tap is connected to the transistor base, the first loop capacitor. one pin of which is connected to the collector of the transistor, and the other through the second loop capacitor to the second lead of the inductance, connected in parallel quartz resonator and correction coil of inductance, which are connected between the junction point of the first and second loop capacitors and the emitter of the transistor, the second blocking capacitor, which connected between the power bus and the common bus, the third resistor, the first terminal of which is the control input of a frequency-controlled crystal oscillator a, and the second output through the varicap is connected to the common busbar, which is in order to extend the tuning range of the frequency and increase the stability of the amplitude of oscillation, the first output of the third resistor through the introduced additional blocking) the capacitor is connected to the common bus, and the second through the introduced additional separating CD 00 capacitor to the base of the transistor. ate 4

Description

I The invention relates to radio nicknames and can be used to create highly stable sources of harmonic oscillations. A frequency-suppressed oscillator is known, containing an active part, a frequency-defining feedback circuit with a quartz resonator, in which the frequency tuning is performed by varying the control voltage on yaricup 1. However, this quartz oscillator has a low level of output power. The closest to the invention in its technical essence is a frequency-controlled crystal oscillator containing a transistor, the emitt of which through the first resistor is connected to the power supply bus, the induction coil, the first output of which is connected to the collector of the transistor, and the second blocking capacitor - to the common bus, resistive divider, which is connected between the second output of the inductor and the power supply, and its tap is connected to the base of the transistor, the first loop capacitor, one output of which is connected to the collector of the transistor, and the other through the second loop capacitor to the second lead of the inductor, connected in parallel quartz resonator and correction coil of inductance, which are connected between the connection point of the first and second loop capacitors and the emitter of the transistor, the second blocking capacitor which is connected between the power bus and the common bus, the third resistor, the first of which is ow. The control input is frequency-yn (Equipped quartz oscillator, and the second output is connected via a varicap to the common bus. In a known frequency-controlled quartz oscillator, the second end of the third resistor is connected via an additional capacitor to the junction point of the first and second contour capacitors C2 The disadvantages of the known frequency-controlled crystal oscillator are the narrow frequency tuning range and amplitude instability of the 4 output signal in the operating range, the purpose of the invention is the extension to frequency tuning and increasing oscillation amplitude stability. This goal is achieved by the fact that in a frequency-controlled crystal oscillator containing a transistor, the emitter of which is connected to the power supply bus through the first resistor, the first output terminal of which is connected to the collector of the transistor and the second through connected in parallel the second resistor and the first blocking capacitor - to the common bus; a resistive divider, which is connected between the second output of the inductor and the power bus; the single transistor capacitor, one output of which is connected to the collector of the transistor, and the other through the second circuit capacitor to the second, the output terminal of the inductance coil, connected in parallel to the quartz resonator and the correction coil of inductance, which are connected between the point of the first and second loop capacitors and the emitter of the transistor, the second block capacitor, which is connected between the power bus and the common bus, the third resistor, the first output of which is a conductive input frequency-controlled crystal oscillator, and the second through vgaod varicap connected to a common bus, a first terminal of the third resistor via a further blocking capacitor is connected to the common bus, and the second through the introduction of additional decoupling capacitor - to the base of the transistor. The drawing shows the electrical circuit of the proposed frequency controlled oscillator. The frequency-controlled crystal oscillator contains a transistor 1, the first resistor 2, the coil 3 inductance, the second resistor 4, the first blocking capacitor 5, resistive divider 6, the first 7 and the second 8 loop capacitors, the crystal resonator 9, the correction coil 10 inductance, the second blocking capacitor 11, thirds | 1 resistor 12, va 1kap 13, block 14 and split 15 additional capacitors.

A frequency-controlled crystal oscillator is a three-point capacitive filtering circuit with a crystal oscillator 9 in a positive feedback circuit. The first 7 and second 8 loop capacitors with coil 3 form a collector circuit. The first 2 and second 4 resistors, as well as the resistive divider 6, set the DC mode. Frequency tuning occurs due to a change in the capacitance of varicap 13 under the influence of a control voltage.

In contrast to the known in the proposed frequency controlled oscillator, when the varicap 13 capacitance changes, the feedback coefficient remains constant, which allows stabilizing the amplitude of oscillations and extending the frequency tuning range.

Experimental studies have shown that in the proposed frequency-controlled crystal oscillator, the change in the amplitude of the output signal is two times smaller, and the tuning range is three times larger than the known one.

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Claims (1)

A FREQUENCY CONTROLLED QUARTZ GENERATOR containing a transistor, the emitter of which is connected through a first resistor to a power bus, an inductor, "the first output of which is connected to a transistor collector, and the second through a second resistor and a first blocking capacitor connected in parallel to a common bus, a resistive divider, which is connected between the second output of the inductor and the power bus, and its tap is connected to the base of the transistor, the first loop capacitor, one terminal of which is connected to the collector of the transistor pa and the other through the second circuit capacitor to the second output of the inductor, a quartz resonator and a correction coil inductance connected in parallel, which are connected between the connection point of the first and second circuit capacitors and the emitter of the transistor, a second blocking capacitor that is connected between the power bus and the common bus, the third resistor, the first output of which is the control input of the frequencies of the no-controlled crystal oscillator, and the second output is connected via a varicap to a common bus, о t The reason is that, in order to expand the frequency tuning range and increase the stability of the oscillation amplitude, the first output of the third resistor is connected to the common bus through the introduced additional blocking capacitor, and the second through the introduced additional isolation capacitor - to the base of the transistor.