SU862351A1 - Crystal-controlled oscillator - Google Patents

Description

(54) QUARTZ GENERATOR

I

The invention relates to radio engineering and can be used in radio communications and radar.

Known crystal oscillator containing two active parts with a quartz resonator 1 connected between them.

However, this generator is not sufficiently high frequency stability simultaneously generated oscillations and mode of operation.

The purpose of the invention is to increase the frequency stability of simultaneously generated oscillations and stability of operation.

To do this, two amplitude detectors, an amplitude comparator, a threshold element, a switch and a DC amplifier are added to a crystal oscillator containing two active parts with a crystal oscillator between them, and the outputs of the active parts are connected to the first and second inputs through the corresponding amplitude detectors amplitude comparator, the output of which is connected to the inputs of the active parts through a series-connected threshold element and switch, and to another input the second active the second part - through an amplifier DC.

The drawing shows a structural electrical circuit of a quartz oscillator.

The quartz generator contains active parts 1, 2, a quartz resonator (CR) 3, amplitude detectors 4, 5, amplitude comparator 6, threshold element 7, switch 8, and DC amplifier 9.

Quartz generator works as follows.

The elements of the active parts 1, 2 provide the condition of the balance of amplitudes and phases for each harmonic of the quartz resonator 3, for example, the first and third. At the moment of switching on the generator, the energy characteristics of one harmonic prevail compared to another, which initially leads to the start of the generator according to one of the harmonics. In this case, for example, the amplitude of the first harmonic of the quartz resonator 3 at the output of the active part 1 has a certain value, and at the output of the active part 2 is equal to zero. The high-frequency voltage from the output of the active part 1 is fed to the input of the amplitude detector 4, detected, and the constant component of the voltage is fed to the first input of the amplitude comparator 6, at the second input of which there is no voltage.

In the absence of equality of the voltages at the inputs of the amplitude comparator 6, a voltage of a defined sign is generated at its output, applied to the input of the threshold element 7. At the output of the threshold element, there is a voltage applied to the input of the switch 8, which provides its switching mode. At the switch output, pulses of different signs appear, including the active part 1 and at the same time turning off the active part 2 and vice versa periodically, with a switching frequency f com. (ft,: f i), where f i is the frequency of the first harmonic KP 3, f t is the frequency of the third harmonic KP 3. As a result, at the outputs of the active parts 1, 2, periodically high-frequency oscillations will occur and the corresponding frequencies fi and fi of the crystal oscillator.

The time constant from the load of the amplitude detectors 4 and 5 is selected from the condition 1 7tb where T4 is the half-period of the RF pulse of one of the harmonics f (or fj, RF voltage at the outputs of the active parts 1 and. 2 are detected by the amplitude detectors 4 and 5 and the approach ts to the inputs of the amplitude comparator 6. Initially, there is a difference in the amplitudes of the RF oscillations of the two harmonics, and at the output of the comparator there is a misalignment signal, which provides switch 8 through the threshold element 7, and, therefore, alternately The operation with the commutation frequency of 1komts active parts 1 and 2. At the same time, the error signal from the amplitude comparator b is also fed through the amplifier 9 to the active part 2, adjusting its DC mode in order to equalize the amplitudes of the RF oscillations with the frequencies fi and fi first and the third harmonic generator.

When the amplitudes of the voltages at the outputs of the active parts 1 and 2 become identical at the output of the amplitude comparator 6, the error signal will be absent. The threshold element 7 will change its state, block switch 8 and provide the simultaneous generation of frequencies fi and fj. When the generator is subjected to destabilizing factors that alter the amplitudes of two harmonics, amplitude comparator 6 and amplifier 9 will maintain, with a certain high accuracy, the state of simultaneous generation of oscillations of the first and third mechanical harmonics of a quartz oscillator due to the automatic alignment of their amplitude values. This will ensure the required high stability of each harmonic and the stability of their simultaneous generation. The proposed device can be used for frequency manipulation of a crystal oscillator using only one crystal oscillator for simultaneous use of a crystal oscillator as a modulated oscillator in transmitters, etc.

Claims (1)

Invention Formula A quartz generator containing the first and second active parts with a quartz resonator connected between them, characterized in that, in order to increase the frequency stability of simultaneously generated oscillations and operation stability, two amplitude detectors, an amplitude comparator, a threshold element, a switch and an amplifier are added to it direct current, the outputs of the first and second active parts through the corresponding amplitude detectors connected to the first and second inputs of the amplitude comparator, the output otorrhea connected to the inputs of the first and second active parts serially connected through a threshold and the switch element and to the other input of the second active part - through an amplifier DC. Sources of information taken into account in the examination 1. USSR author's certificate in application No. 2538942 / 18-09, cl. H 03 H 5/32, 11/01/77 (prototype).  Have