|
SIMPLE
IF SIGNAL GENERATOR
|
Here
is a versatile circuit of IF signal generator which may
be of interest to radio hobbyists and professionals alike.Transistors
T1 and T2 form an astable multivibrator oscillating in
the audio frequency range of 1 to 2 kHz. RF oscillator
is built around transistor T3. Here again a 455kHz ceramic
filter/resonator is employed for obtaining stable IF.
The AF from multivibrator is coupled from collector of
transistor T2 to emitter of transistor T3 through capacitor
C3. The tank circuit at collector of transistor T3 is
formed using medium wave oscillator coil of transistor
radio, a fixed 100pF capacitor C5 and half section of
a gang capacitor (C6).
The oscillator section may be easily modified for any
other intermediate frequency by using ceramic filter or
resonator of that frequency and by making appropriate
changes in the tank circuit at collector of transistor
T3. Slight adjustment of bias can be affected by varying
values of resistors R6 and R7, if required. |
|
|
Click on the Image for its larger version
|
