Propose a scheme GWh with enhanced stability (Fig.1). She has large input and output impedance and lower output capacity than the standard inductive type.
The transistors included in the scheme "Common stock common base", VT1 is used for decoupling. The output voltage of the generator is 0.1…0.2. In the collector circuit VT1 can be enabled (required through resistor 50… 100 Ohm) auxiliary circuit, tuned to the fundamental frequency or harmonic. Possible options for the inclusion of the basic circuit shown in Fig.2. The capacitor C2 may have a capacity of about one picofarad. The R2 engine installed in the bottom under the scheme the position and move to the lasing at the lowest frequency of the circuit. To obtain the harmonics of the engine is set higher. If stability is not as important as the desired uniformity in amplitude, use the enable circuit. Low band-its shunt resistor value is somewhat com.
When you turn on the scheme of Fig.2A have a number of turns to drain in the coil L1 to achieve generation at the lower frequency of the circuit, since the excitation occurs at the parasitic frequency the lower part of the coil.
In the diagram Fig.2 g of the capacitance C2 for SW bands - several hundred picofarads. Quartz ZQ excited and also on the harmonics.
The generator operates at a voltage of 7…24 V. Its disadvantage is the initial run frequency as the voltage on the circuit can be tens of volts (in the scheme of Fig.2E it is equal to the SSI VT3). C6 must have a minimum length of the conclusions of the Generator is stable at frequencies from 10 kHz to 200 MHz and higher (determined by parasitic capacitance СкэVT3).
Author: V. Klimovich, G. p. B. berestovica; Publication: N. Bolshakov, rf.atnn.ru