Ch1 Display And Output - Stanford Research Systems SR844 User Manual

CH1 Display and Output

The keys in this section select the Channel 1 display
quantity and analog CH1 OUTPUT, as well as offsets,
expands and ratios.
Display
This key selects the Channel 1 Display quantity. Channel 1 may display X [Volts], R
[Volts], R [dBm], Xnoise [Volts], or AUX IN 1 [Volts]. The displayed quantity appears
on a 4½ digit display and also on the accompanying bar-graph display. An indicator
shows the currently displayed quantity.
Quantity
X
R [V]
R [dBm]
Xnoise
AUX IN 1
Description
This is the component of the input signal in-phase with the reference. The
reference phase may be adjusted; see the section on Reference Phase later in
this chapter for more information.
This is the magnitude of the input signal, measured in Volts. Note that R is
computed from the filtered values of X and Y, so that a signal with constant
R and rapidly-varying phase (compared to the time constant) will give an
incorrect value for R.
This is the magnitude of the input signal, measured in dBm. The conversion
from Volts to dBm assumes a 50
This is the input signal noise at the reference frequency, and is derived from
the X measurements. This quantity is discussed in greater detail in Chapter
2, Noise Measurements.
This is the voltage applied to the rear panel AUX IN 1.

CH1 Display and Output 3-15

Ω
load.
SR844 RF Lock-In Amplifier