Performance Tests - Stanford Research Systems SR554 Manual

Performance tests are designed to verify
that the unit is performing within the
specifications.
Necessary Equipment:
1. Lock-In Amplifier
Range 0.1 Hz - 100 kHz
Output Ampl 4 mV rms - 1 Vrms
50 Ω
Output Z
Recommended SRS
2. 50 Ω Ω Ω Ω  T erminator
3. 50 Ω Ω Ω Ω , 20 dB Attenuator
The instructions here apply to SRS DSP
lock-ins (SR850/830/810). Other lock-in
amplifiers may be used. However they will
require substantially longer time constants
to arrive at accurate measurements.
1) Connect the 9-pin power cable from
the rear of the lock-in amplifier to the
SR554. Connect the 20 dB attenuator
to the lock-in reference output and a
BNC cable from that to the SR554
(A) input. Connect another BNC cable
from the SR554's (A) output to the
lock-in's (A) input. Set SR554 to
buffered mode (X500), (A) input.
2) Power on the lock-in in the default
condition. (SR810/830 Power on
Setup, SR850 Power on Bksp) This
places the lock-in in a known state.
The power LED of the SR554 should
light.
3) Set the input to DC coupled, grounded
shield. Set the time constant to 300
ms (1 s for 1 Hz measurement), 12
dB/oct filter and turn on synchronous
filtering (if available). Set the display
type to magnitude (R) and the
reference sinewave amplitude to 10
mV rms.

PERFORMANCE TESTS

Freq
SR850/830/810
9
4) For each frequency, the following
amplitude should be observed, ± 5%.
Frequency Amplitude
1.0 Hz 31 mV
10 Hz 252 mV
100 Hz 438 mV
200 Hz 442 mV
500 Hz 439 mV
1 kHz 414 mV
10 kHz 96 mV
100 kHz 11 mV
5) Disconnect the lock-in reference from
the SR554 input. Connect the 50 Ω
terminator to the SR554 (A) input.
6) Set the lock-in to measure noise.
7) For each frequency and time constant,
the following rms noise voltage should
be observed (±10%). Set the lock-in
sensitivity to about 5 times the
expected reading and allow it to settle
(10-20 time constants) before making
readings.
Frequency Time Constant Noise
Voltage
1.0 Hz 3.0 s
10 Hz 1.0 s
100 Hz 0.1 s
200 Hz 0.1 s
500 Hz 0.1 s
1 kHz 0.03 s
10 kHz 0.03 s
100 kHz 0.03 s
480 nV
260 nV
460 nV
460 nV
460 nV
420 nV
120 nV
60 nV