Wavetek 180 - Function Selections; Sweep Controls; Operation; Signal Termination

counterclockwise, negative. When OFF, the wave
form is balanced around signal ground (figure 3-2).
TTL PULSE
Figure 3-2. Output Waveforms
@ AMPLITUDE
Rotating the AMPLITUDE control fully clockwise
provides maximum peak-to-peak output at the
50n OUT connectors; counterclockwise for up to
30 dB attenuation of output amplitude.
50n OUT Connectors
Maximum output of 10V p-p signals into a 5012
load (20V p-p open circuit) is provided at the
50n OUT HI connector, and 20 dB below (1/10
or a 1V p-p maximum) of that level at the 5012 OUT
LO connector.
3.1.3 Function Selections
(D %
Tj , and DC (Waveforms)
Sine 'V , triangle 'V , and square ""L wave
forms are selected by the larger of the two concen
tric controls; the DC position provides a dc voltage
output of the waveform center reference level at
the 5012 OUT connectors.
@ TTL PULSE OUT Connector
A fixed amplitude Transistor-Transistor Logic
(TTL) square pulse train of the output frequency
is provided at the PULSE OUT (TTL) connector.
(TTL levels are OV to 0.4V for a logic low and
2.4V to 5V for a logic high.) The output can drive
up to 20 TTL loads. The pulse train can also be
used as a synchronizing reference for the main
output @ . Phase of the waveforms relative to
the TTL pulse is shown in figure 3-2.
3.1.4 Sweep Controls
@ SWEEP WIDTH/OFF
Main output (at 5012 OUT HI or LO) frequency
sweep is turned on when SWEEP WIDTH is rotated
past OFF. Rotation of the control varies the peak
amplitude of an internal ramp signal (seen at GCV
OUT) whose voltage controls the frequency of the
main generator (seen at 5012 OUT). See figure 3-3.
. SWEEP TIME
GCV
OUT
5012
OUT
SWEEP START
FREQUENCY SET BY
FREQUENCY DIAL
SWEEP
WIDTH
SWEEP STOP
FREQUENCY SET BY
SWEEP WIDTH
Figure 3-3. Effect of Sweep on Output Frequency
SWEEP OUT Connector
The sweep generator ramp is available at the
SWEEP OUT connector. Amplitude is OV to 5V
peak (60012 source impedance).
SWEEP RATE
Rotation of SWEEP RATE controls duration of
the sweep voltage ramp, and thus frequency of
sweep repetition.
3.2 OPERATION
Operation can be quite varied but is described here as
manual, voltage controlled or sweep controlled. The gen
erator is ready to operate as soon as a frequency multiplier
is selected; however, when output is critical, allow Vi hour
warm up.
3.2.1 Signal Termination
Proper signal termination, or loading, of the generator con
nectors is necessary for its specified operation. For example,
the proper termination of the main output is shown in
figure 3-4. Placing the 50 ohm terminator, or 50 ohm
resistance, in parallel with a higher impedance, matches
the receiving instrument input impedance to the generator
3-2