NF WF1945B, Instruction Manual

Page: 39 / 188

3.2 Input and output connections
WF1945B
3-9
„
Trigger/sweep input (TRIG/SWEEP IN)
Signal characteristics:
The following types are produced during the burst oscillation mode.
Trigger: Select oscillation start for either or .
Gate: Select oscillation at either high or low level.
Triggered gate: Oscillation start/stop at
or . Select either.
Minimum pulse width is 50 ns.
In sweep oscillation mode, the sweep starts at or . Select either.
Minimum pulse width is 200 ns.
Input voltage :
High level
≥
+3.9 V
Low level
≤
+1.6 V
Input voltage range :
−
0.5 to +5.5 V
Input impedance : Pull up to +5 V at approx. 10 k
Ω
Ground : Connected to chassis ground
Do not apply a signal exceeding the above input voltage range. The unit can be damaged.
• Drive circuit examples
Connect the trigger and sweep input drive signals to TTL or C-MOS logic IC outputs.
Since the input circuit is provided with a built-in pullup resistor, an open collector output drive can also be
used. However, contact chatter from a mechanical switch or relay can prevent normal operation. Also,
chattering will prevent normal operation when the oscillation mode is triggered gate.
Avoid using a logic IC circuit having a power supply voltage higher than +5 V such as example (c) for the
WF1945B input
! CAUTION
+5 V
+12 V
～
(a) TTL logic output (b) Open collector output (c) High voltage logic output
TRIG/SWEEP IN
+5 V
10 k
Ω
100
Ω
D