Stanford Research Systems SR844, User Manual

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SR844 RF Lock-In Amplifier
Specifications
Specifications apply after 30 minutes of warm-up. All specifications are with output filtering enabled (6,
12, 18 or 24 dB/oct) and 2F detection OFF, unless stated otherwise.
Signal Input
Voltage Input single-ended BNC.
Input Impedance 50
Ω
or 1 M
Ω
|| 30 pF.
Damage Threshold ± 5 V (DC+AC)
Bandwidth 25 kHz to 200 MHz.
Full Scale Sensitivity 100 nV to 1V rms in a 1-3-10 sequence.
Gain Accuracy
< 50 MHz
±
0.25 dB
< 200 MHz ± 0.50 dB
Gain Stability 0.2%/ ° C
Coherent Pickup Low Noise Wide Reserve, Sensitivity < 30 mV.
f < 10 MHz < 100 nV (typical)
f < 50 MHz < 2.5
µ
V (typical)
f < 200 MHz < 25
µ
V (typical)
Input Noise: 50 Ω Input
100 kHz < f < 100 MHz 2 nV/ √ Hz (typical), < 4 nV/ √ Hz (max).
25 kHz < f < 200 MHz < 5 nV/ √ Hz (typical), < 8 nV/ √ Hz (max).
Input Noise: 1 M Ω Input
25 kHz < f < 200 MHz 5 nV/ √ Hz (typical), < 8 nV/ √ Hz (max).
Dynamic Reserve > 60 dB (expand off)
Reference
External Reference Input 25 kHz to 200 MHz.
Impedance 50
Ω
or 10 k
Ω
|| 40 pF.
Level 0.7 Vpp digital or 0 dBm sinusoidal signal.
Pulse Width > 2 ns at any frequency.
Threshold Setting Automatic, set to midpoint of waveform extrema.
Acquisition Time < 10 s (auto-ranging, any frequency).
< 1 s (within same octave).
Internal Reference Oscillator 25 kHz to 200 MHz.
Frequency Resolution 3 digits.
Frequency Accuracy
±
0.1 in the 3rd digit.
Phase Noise
-
90 dBc/Hz at f=100 MHz,
∆
f=100 Hz.
Reference Outputs Phase locked to either Internal or External reference.
Front Panel Ref Out 25 kHz to 200 MHz square wave, 1.0 Vpp nominal into 50
Ω
.
Rear Panel TTL Out
25 kHz to 1.5 MHz, 0 to +5 V nominal,
≥
3 V into 50
Ω
.
Harmonic Detect
Detect at 50 kHz ≤ 2
×
Reference ≤ 200 MHz.
Phase Resolution 0.02
°
Absolute Phase Error
< 50 MHz < 2.5 °
< 100 MHz < 5.0 °
< 200 MHz < 10.0 °