Stanford Research Systems SR830, Manual

Page: 14 / 177

2-3
THE BASIC LOCK-IN
This measurement is designed to use the internal oscillator to explore some of the basic lock-in functions.
You will need BNC cables.
Specifically, you will measure the amplitude of the Sine Out at various frequencies, sensitivities, time con-
stants and phase shifts.
1. Disconnect all cables from the lock-in. Turn
the power on while holding down the [Setup]
key. Wait until the power-on tests are
completed.
2. Connect the Sine Out on the front panel to the
A input using a BNC cable.
3. Press [Auto Phase]
4. Press [Phase]
5. Press the [+90°] key.
When the power is turned on with the [Setup] key
pressed, the lock-in returns to its standard default
settings. See the Standard Settings list in the
Operation section for a complete listing of the
settings.
The Channel 1 display shows X and Channel 2
shows Y.
The lock-in defaults to the internal oscillator refer-
ence set at 1.000 kHz. The reference mode is indi-
cated by the INTERNAL led. In this mode, the
lock-in generates a synchronous sine output at the
internal reference frequency.
The input impedance of the lock-in is 10 M
Ω
. The
Sine Out has an output impedance of 50
Ω
. Since
the Sine Output amplitude is specified into a high
impedance load, the output impedance does not
affect the amplitude.
The sine amplitude is 1.000 Vrms and the
sensitivity is 1 V(rms). Since the phase shift of the
sine output is very close to zero, Channel 1 (X)
should read close to 1.000 V and Channel 2 (Y)
should read close to 0.000 V.
Automatically adjust the reference phase shift to
eliminate any residual phase error. This should set
the value of Y to zero.
Display the reference phase shift in the Reference
display. The phase shift should be close to zero.
This adds 90° to the reference phase shift. The
value of X drops to zero and Y becomes minus the
magnitude (-1.000 V).
The Basic Lock-in