Voltage-Controlled Shf Oscillator

I oI This oscillator supplies an output level between -10 dBm and +3 dBm, and can be tuned between 1250 MHz and 1800 MHz simply by varying the supply voltage. Operation of the circuit is based on the fact that the transition fre- quency, fr, of the BFG65 is reduced when the collector current rises above 10 mA. The oscillation frequency is also determined by the physical layout of in- ductor L3, which is a strip line made from two parallel running lengths of 1 mm dia. silver plated wire. The length is established experimentally, starting from 13 mm. Chokes Li and La are 3 turns of thin enamelled copper wire (dia. 0.2 or 0.3 mm) through a small (3 mm) ferrite bead. Capacitors Ca and Ca are leadless ceramic types (rec- tangular or disc). The SHF test oscillator is ideal for quickly finding the maximum usable in- put frequency of, for instance, a fre- quency meter specified to reach up to 1.2 GHz. In addition, it can be used for testing RF input sections in indoor units for satellit...