DEVICE FOR THERMAL CORRECTION OF CRYSTAL OSCILLATOR Russian patent published in 1994 - IPC

FIELD: electric engineering. SUBSTANCE: device has crystal oscillator 1 having positive thermal effect on generated frequency, crystal oscillator 2 having negative thermal effect on generated frequency, frequency difference detector 3, frequency divider 4, first counter 5, second counter 6, first RS flip-flop 7, matching gate 8, third counter 9, digital comparator 10, NAND gate 11, second RS-flip-flop 12, OR gate 13. Frequency difference detector 3 detects difference between frequencies of crystal oscillators 1 and 2. This difference is converted by frequency divider 4 into number of pulses which is stored in counter 5. Then by means of first and second RS-flip-flops 7, 12, third counter 9 and digital comparator 10 this number is added to number of pulses running through second counter 6. This results in generation of standard time duration that corresponds to standard frequency. EFFECT: increased speed and increased precision of thermal correction. 2 dwg