| 摘要 |
1,118,963. Frequency modulation; semiconductor circuits. GENERAL PRECISION Inc. 6 July, 1965 [6 July, 1964], No. 28656/65. Headings H3R and H3T. A voltage controlled oscillator includes a tuned circuit comprising an inductance 13 in parallel with the series combination of a diode 15 and a capacitor 14, coarse control of frequency being made by adjustment of the inductance 13 and fine control by adjustment of the voltage applied at the junction 18 of the diode and capacitor. As shown, the tuned circuit is connected to the collector of transistor 11, feedback to the emitter being provided via capacitor 16. The oscillator may form part of a vehicle detector wherein presence of a vehicle in loop 21 affects the frequency of oscillator 20 to which the frequency of the voltage controlled oscillator is locked by a mixer 22 and discriminator 25 which supplies the control voltage at point 18. The output of the oscillator is a distorted sine wave, Figs. 3 and 4 (not shown), which may be converted to a sine wave or a square wave by a filter or a buffer amplifier. |
