Stanford Research Systems SR810 Manual page 56

Front Panel
[Time Constant Up/Dn]
The actual dynamic reserves (in dB) for each sensitivity are listed below.
Sensitivity Low Noise
1 V
500 mV
200 mV
100 mV
50 mV
20 mV
10 mV
5 mV
2 mV
1 mV
500 µV
200 µV
100 µV
50 µV
20 µV
10 µV
5 µV
2 µV
1 µV
500 nV
200 nV
100 nV
50 nV
20 nV
10 nV
5 nV
2 nV
Do not use ultra high dynamic reserves above 120 dB unless absolutely
necessary. It will be very likely that the noise floor of any interfering
signal will obscure the signal at the reference and make detection
difficult if not impossible. See the SR810 Basics section for more
information.
Auto Reserve
Pressing [AUTO RESERVE] will change the reserve mode to the
minimum reserve required. Auto Reserve will not work if there are low
frequency noise sources which overload infrequently.
This key selects the time constant. The time constant may be set from
10 µs to 30 s (detection freq.>200 Hz) or 30 ks (detection freq. <200 Hz).
The detection frequency is the reference frequency times the harmonic
detect number. The time constant is indicated by 1 or 3 times 1, 10 or
100 with the appropriate units.
The maximum time constant is 30 s if the detection frequency is above
200 Hz and 30 ks if the detection frequency is below 200 Hz. The actual
range switches at 203.12 Hz when the frequency is increasing and at
199.21 Hz when the frequency is decreasing. The time constant may not
be adjusted beyond the maximum for the present detection frequency. If
the detection frequency is below 200 Hz and 100 s is the time constant
4-8
Normal High Reserve
0 0
6 6
4 14
0 10
6 16
4 24
0 20
6 26
4 34
10 40
16 46
24 54
30 60
36 66
44 74
50 80
56 86
64 94
70 100
76 106
84 114
90 120
96 126
104 134
110 140
116 146
124 154
0
6
14
20
26
34
40
46
54
60
66
74
80
86
94
100
106
114
120
126
134
140
146
154
160
166
174