3
rd
Generation Rack-
Mount RDMS™
43
Quasonix, Inc.
Figure 57: AGC Menu, Polarity Highlighted
4.4.2.16.2 AGC Scale
The AGC Scale option, shown in Figure 58, adjusts the voltage of the AGC back panel BNC output. The scale can
be set in units of dB/V (decibels per volt). The higher the scale is set, the more dynamic range the AGC output can
represent, but the lower its resolution will be. The AGC output is calibrated to a load of 1 KOhm. Operation into
other load impedances will result in the effective AGC scale factor being higher or lower than expected.
For example, suppose the AGC zero point is -100 dBm. The AGC output will be 0.0 V when no input signal is
applied. When a signal of -80 dBm is received (i.e., 20 dB above the zero point), then the AGC output will be 2.0 V
if the scale is set to 10 dB/V and 1.0 V if the scale is set to 20 dB/V. The maximum AGC output voltage is ±5.0 V.
To change the AGC Scale value, select AGC Scale, then press the Enter key on the front panel. An entry screen
(Figure 58) prompt
s the operator to type a new AGC Scale value, in db/V, using the rack’s front panel numeric
keypad. When the new value is entered, press the Enter key on the keypad.
Figure 58: AGC Menu, AGC Scale Selection and Entry Screens
4.4.2.16.3 AGC Time Constant
The Time Constant option, shown in Figure 59, sets the time constant of the AGC back panel BNC output. The time
constant can be set in units of ms (milliseconds). The higher the time constant, the slower the AGC output voltage
will move in response to changes in input signal level.
