Multifrequency control from a single crystal
First Claim
1. A circuit for regulating the output frequencies of a number of voltage controlled oscillators including a crystal capable of simultaneous vibration in more than one mode at different frequencies, the crystal being connected between the output of a summing amplifier and the input of a buffer amplifier, a number of voltage controlled oscillators each being supplied with a variable DC voltage for controlling its frequency, the outputs of the voltage controlled oscillators being supplied to the summing amplifier, and a phase detector associated with each oscillator for receiving the output of each voltage controlled oscillator and the output of the buffer amplifier for the purpose of generating a DC voltage proportional to the phase difference between the output of the oscillator and the buffer amplifier and supplying it to the associated oscillator to control its frequency.
2 Assignments
0 Petitions
Accused Products
Abstract
A piezo-electric crystal vibrating in several modes controls several frequencies generated by voltage controlled oscillators simultaneously. The output of each voltage controlled oscillator is fed to a summing amplifier which drives the crystal. The output of the crystal is fed to individual phase detectors; each phase detector is also supplied with the output of a voltage controlled oscillator and generates a voltage proportional to the phase difference between the voltage controlled oscillator and the crystal output for correcting the output frequency of each oscillator.
17 Citations
7 Claims
- 1. A circuit for regulating the output frequencies of a number of voltage controlled oscillators including a crystal capable of simultaneous vibration in more than one mode at different frequencies, the crystal being connected between the output of a summing amplifier and the input of a buffer amplifier, a number of voltage controlled oscillators each being supplied with a variable DC voltage for controlling its frequency, the outputs of the voltage controlled oscillators being supplied to the summing amplifier, and a phase detector associated with each oscillator for receiving the output of each voltage controlled oscillator and the output of the buffer amplifier for the purpose of generating a DC voltage proportional to the phase difference between the output of the oscillator and the buffer amplifier and supplying it to the associated oscillator to control its frequency.
Specification