Table of Contents
Advertisement
3. Operation
General.
First ascertain that the Beat Frequency Oscillator is set to the appropriate
power supply voltage by means of the selector at the rear of the instrument
and that the Remote Control plug on the front panel is firmly home.
A. Frequency Calibration.
14
1. Snap the toggle switch marked POWER to "On" and allow two minutes
to warm up.
2. Set MODULATION FREQUENCY and COMPRESSOR SPEED switches
to their "Off" position.
3. Check that the frequency incremental scale is on zero.
If
not, set by
FREQUENCY INCREMENT KNOB to this point.
4. Turn main scale pointer to frequency which is "4" times that of the
line voltage (e.g. 200 for a 50 Hz mains). The fine adjustment knob of
the main scale pointer is operated by pressing and turning.
5. Set suitable deflection on meter by turning knob marked OUTPUT
VOLTAGE to higher than center scale reading.
6. Press LINE FREQUENCY BEAT button and hold to "in" position and
at the same time rotate FREQUENCY SCALE ALIGNMENT "Fine"
slowly, until a large fluctuation registers, slows up, and practically
ceases on the meter dial. Two points may be found where this occurs,
only one of which is correct and therefore a check as outlined in the
following paragraph should be carried out, firstly releasing the LINE
FREQUENCY BEAT button.
7. With the FREQUENCY INCREMENT knob, reduce total scale reading
to 0 (i.e. mains scale reading
+
incremental scale reading
=
0).
If
fre-
quency calibration is correct meter needle will drop to zero indicating
that the BFO is properly tuned.
If
not, readjust FREQUENCY SCALE
ALIGNMENT to obtain zero meter deflection and repeat procedure
from item 3 through 6.
9. Finally return FREQUENCY INCREMENT to zero and BFO is ready
for use.
Note:
If
zero point cannot be found and is outside the range of the FRE-
QUENCY SCALE ALIGNMENT "Fine" re-align the variable capacitor
marked "Coarse" with a screwdriver to give a suitable setting which
Advertisement
Table of Contents
