| 摘要 |
1,025,979. Frequency modulation. SIEMENS & HALSKE A.G. Sept. 16, 1963 [Sept. 28, 1962], No. 36290/63. Heading H3R. Modulation is applied through terminals 6 to reactor diodes 3, 2, in the frequency determining collector circuit of a transistor oscillator to produce frequency modulation. To improve the frequency modulation linearity a series resonant but highly damped circuit 18, 17, 16 is connected between a tapping of the collector inductor 1 and the oscillator load 16 and is resonant above the maximum frequency excursion of the oscillator, and so tends to reduce the total reactance of the collector circuit and assists in increasing the modulated frequency as the modulation increases it. The emitter circuit 11, 12 is also tuned and Ct is a feedback capacitor. A section of coaxial transmission line terminated by its surge resistance R may alone form the circuit 18, 17, 16, stray inductance forming the inductor 18. Also stray inductance of the coil 1 regarded as an auto-transformer may replace the inductor 18. The system may be applied to multiplex FM relay systems. |
