Specifications

Measurement Examples
20
1. Turn the SR400 off. Hold down the STOP (RESET) button while turning the SR400 on. Wait three seconds
and release the button.
2. Press the MODE key. Using the four arrow keys and the front panel knob, select the following parameters.
Unless otherwise indicated, leave all other settings at their default values:
T = 10 MHz TSET = 9E-1 s
N PERIODS = 10 [AT 0]
AT N = STOP DWELL = EXTERNAL (Turn the knob counterclockwise until “DWELL = EXTERNAL” is
displayed.)
3. Press the A GATE key and select the following parameters:
A GATE = FIXED
A DELAY = 300 mS
A width = 500 mS
4. Press the LEVEL key and select the following parameters:
A DISC SLOPE = RISE
A DISC LVL = +150 mV
5. Using a function generator or a pulse generator, apply a 1 Hz, 5 V (TTL) signal to the EXTERNAL
START input on the SR400. Use a BNC ‘T; connector at the EXTERNAL START input and extend a cable
from the EXTERNAL START input to the TRIG input.
6. Using a second signal source, apply a 10 kHz square wave (or pulse train) with an amplitude of
approximately 500 mV to the SIGNAL INPUT 1 on the SR400.
7. To view the COUNT PERIODS, press the MODE key and use the up/down arrow keys to display “N
PERIODS = 10 [at 0]”
8. Arm the SR400 by pressing the STOP (RESET) button.
Each counting period should result in approximately 5,000 counts. After 10 counting measurements the
SR400 will disarm. To re-arm, press the STOP (RESET) button.