IBM 7220, Instruction Manual

Page: 88 / 155

6-12
Chapter 6, COMPUTER OPERATION
ASM Perform an Auto-Measure operation
The instrument adjusts its full-scale sensitivity so that the magnitude output lies
between 30 % and 90 % of full-scale, and then performs an auto-phase operation to
maximize the X output and minimize the Y output.
ACGAIN [n] AC Gain control
Sets the gain of the signal channel amplifier. Values of n from 0 to 9 can be entered,
corresponding to the range 0 dB to 90 dB in 10 dB steps.
AUTOMATIC [n] AC Gain automatic control
The value of n sets the status of the AC Gain control according to the following table:
n Status
0 AC Gain is under manual control, either using the front panel or the ACGAIN
command
1 Automatic AC Gain control is activated, with the gain being adjusted
according to the full-scale sensitivity setting
LF [n] Signal channel line frequency rejection filter control
In instruments manufactured prior to June 1996, the value of n sets the mode of the
line frequency notch filter according to the following table:
n Selection
0 Off
1 On (i.e. reject 50/60 Hz and 100/120 Hz)
In instruments manufactured after June 1996, the value of n sets the mode of the line
frequency notch filter according to the following table:
n Selection
0 Off
1 Enable 50 or 60 Hz notch filter
2 Enable 100 or 120 Hz notch filter
3 Enable both filters
Users may identify which version of the instrument they have by sending the
command LF 3; if this is accepted by the instrument, it was made after June 1996,
but if it generates a command error, it was made prior to this date.
Units made after June 1996 respond in addition to a new command, LINE50, which
sets the notch filter centre frequency.
LINE50 [n] Signal channel line frequency rejection filter centre frequency control
The value of n sets the line frequency notch filter centre frequency according to the
following table: