Bandwidth Test - Elenco Electronics AM/FM-108CK Assembly And Instruction Manual

Generator
Hz

BANDWIDTH TEST

Connect your test equipment to the circuit as shown
in Figure 40. Set your generator at 10.7MHz no
modulation and minimum voltage output. Set the
scope for 10mV per division. Turn the power ON and
slowly increase the amplitude of the generator until
40mVpp are seen on the scope.
frequency until the voltage drops .707 of its original
value, 2.8 divisions or 28mVpp.
frequency of the generator until the voltage drops
.707 of its original value, 2.8 divisions or 28mVpp.
Record the frequency of the low 3dB drop-off point
here:
Fl = _________MHz.
FM OSCILLATOR ASSEMBLY INSTRUCTIONS
C7 - .001μF Discap (102)
R4 - 33kΩ Resistor
(orange-orange-orange-gold)
Q2 - 2N3904 Transistor
(see Figure C)
R5 - 33kΩ Resistor
(orange-orange-orange-gold)
R6 - 2.2kΩ Resistor
(red-red-red-gold)
C8 - .005μF Discap (502)
.001μF
TP15
Increase the
Record the
Probe
Figure 40
Turn the power OFF.
calculated as follows:
Your calculated answer should be between 300 -
500kHz.
Record your calculation:
Bandwidth = _________kHz.
-44-
Oscilloscope
The bandwidth can be
Bandwidth = Fh - Fl
L3 - FM Oscillator Coil
(5 Turns)
C9 - 15pF Discap (15)
C10 - 30pF Discap (30)
C11 - 220pF Discap (221)
TP15