Stanford Research Systems SR124, Operation And Service Manual

Page: 11 / 85

General Information ix
Demodulator / Output
Parameter Specification
Output gain stability
Low noise 50 ppm
/
◦
C
Normal 100 ppm
/ ◦
C
High reserve 1000 ppm
/
◦
C
Output filter − 6 dB
/
oct or − 12 dB
/
oct
Time constants 1 ms to 300 s in 1–3–10 steps
Output impedance 600
Ω
Reference channel
Parameter Specification
Frequency range 0.2 Hz to 210 kHz
Reference input TTL or sine, 100 mVrms min. f
>
2 Hz,
500 mVrms min. f ≤ 2 Hz
locks to positive-going zero crossing (sine),
positive edge (TTL).
Minimum pulse width 100 ns (TTL mode)
Input impedance 1 M
Ω
AC coupled, 10 s time constant (sine)
DC coupled (TTL)
Phase resolution 0.01
◦
Phase accuracy ± 5
◦
(2 Hz to 20 kHz)
± 10
◦
(20 kHz to 210 kHz)
Harmonic detection F, 2 × F, and 3 × F (ext. ref.)
Reference output
Parameter Specification
Range 0.2 Hz to 210 kHz
Waveform sine, square
Frequency accuracy ± 0.1% (20 Hz to 21 kHz)
Frequency resolution 3-1
/
2 digits or 1 mHz
Amplitude range 100 nV to 10 Vrms into high-Z
Amplitude accuracy ± 1% at 1 kHz (on 20 Hz to 2.1 kHz range)
Amplitude flatness
±
1% for upper decade of each range
± 5% for lower decade of each range
Amplitude stability 50 ppm
/
◦
C, typ.
Output impedance 50
Ω
DC bias commandable, to ± 10 × amplitude,
or ± 10 VDC max (amp. dependent;
see section 3.4 for details)
SR124 Analog Lock-In Amplifier