Stanford Research Systems SR844, User Manual

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3-40 Scan - Rel
SR844 RF Lock-In Amplifier
Rels without Scan
This section discusses the storage of Rel Values when the unit is not in Scan mode. This is useful for
external reference configurations or for frequency points that are not in a log series. Up to 11 different Rel
Configurations may be stored (at 11 different frequencies).
To store Rel Values at the current frequency:
•
Use the
Store XY
key to Auto Offset X and Y and store the offsets as XY Rel offset values. The
XY READY indicator is on when XY Rel Values have been stored at the current frequency. This also
stores the Rel Configuration (sensitivity, reserve, etc.).
•
Use
STORE R[dBm]
θ
(
Shift–Store XY
) to Auto Offset R[dBm] and Auto Phase the reference and
store the results as R[dBm] and
θ
Rel offset values. The R[dBm]
θθθθ
indicator is on when R[dBm]
θ
Rel
Values have been stored at the current frequency. This also stores the Rel Configuration (sensitivity,
reserve, etc.).
Use the Rel Mode key to toggle REL MODE on and off.
With
REL MODE
on, the instrument automatically recalls the stored Rel Configuration and Rel Values
whenever the frequency is within 1% of a frequency for which a Rel Configuration and Values has been
stored. The
REL indicator within the CH1 and CH2 displays is on whenever the recalled Rel
Configuration and Rel Values are in effect.
If the current frequency does not have any stored Rel Values (as indicated by XY READY or R[dBm]
θθθθ
)
,
the current configuration and offsets remain in effect. The REL indicator is off in this case.
The stored XY Rel Values are applied as X and Y offsets (adjusted for the current phase). The stored
R[dBm] Rel Value is applied as the R[dBm] offset. The stored
θ
Rel Value is applied as the Reference
Phase (there is no phase offset). Offset indicators within the CH1 and CH2 displays are turned on as
appropriate (as well as the
REL indicator).
After the Rel Configuration and Rel Values are recalled, the instrument setup can be modified using the
front panel or remote interface. Once the configuration is modified, the
REL
indicator turns off indicating
that the current configuration is not the recalled Rel Configuration. Toggle REL MODE off and back on to
recall the stored Rel Configuration once again.
When
REL MODE
is off, stored Rel Configurations and Rel Values are ignored (the configuration and
offsets currently in effect are still applied to the measurement).
•
Pressing
CLEAR ALL
clears all stored Rel Configurations, both those stored with a scan and those
stored at specific frequencies.
•
Pressing the CLEAR ONE clears the Rel Configuration stored with the current frequency (if any).
•
The Rel Configurations are indexed by frequency with a 1% tolerance band. Rels stored at 90.0MHz
will be recalled whenever the frequency falls between 89.1MHz (-1%) and 90.9MHz (+1%).
•
You should familiarize yourself with the preceding sections before using the Rels without Scan.