Wavetek 171 Manual page 21

quency із divided by а multiple of 10, as controlled by the
FREQ MULT range switch, and fed to the function generator
phase lock loop (figure 4-1).
A 10k to 200 kHz output is used to create the F/V signal
which gives rapid function generator response to frequency
changes. A one-shot changes the signal to fixed width pulses
whose spacing is frequency dependent. These are converted
CLK
KILL
XTAL OSC/
24 РНА5Е
1.0000 kHz DETECTOR
1 MHz Í
EXT/INT
REF j $74
SELECTION D
1 MHz 1.0000 kHz
EXT REF
IN
0.1000 - 1.9999
DIGITAL
FCTN SWITCH
GEN
MODE SW CLK
e KILL
SYNTHE-
SIZER
FIV FIV ONE- 10k - 200 kHz
CONV SHOT
FCTN GEN
+26V
CLK INDICATOR
KILL SELECTOR
SYNTHESIZER
to a frequency dependent voltage level at the F/V converter
output.
One pole of the function generator/synthesizer mode switch
furnishes the ground signal CLK KILL. CLK KILL stops
synthesizer loop activity when the instrument is in function
generator mode or set on X 1, a dial-only range. Lamps in-
dicating mode are also controlled by this CLK KILL.
OUT
TTL BUFFER 1 MHz С
(ОРТІОМ)
CLK KILL 8M - 20 MHz
+10R
FREQUENCY SYNTHESIZER LOOP
FREQUENCY (REF)
RANGING
Figure 4-5. Synthesizer Phase Lock Loop
43