564 Chapter13
Softkey Descriptions
Softkey Descriptions
CAL AMPTD Calibrate Amplitude
DESCRIPTION Note that if both CAL FREQ and CAL AMPTD
self-calibration routines are required, perform the CAL
FREQ routine first.
The
CAL AMPTD softkey initiates an amplitude
self-calibration routine. Connect CAL OUT to the
analyzer input before pressing
CAL AMPTD.
During the
CAL AMPTD self-calibration routine,
messages are sequentially displayed, indicating a
specific calibration activity. Each calibration performed
by
CAL AMPTD is described below.
• While CAL: AMPTD is displayed, the following
calibrations are performed:
❏ The amplitude error of eachresolution bandwidth
is corrected using the 3 kHz resolution bandwidth
is the amplitude reference. Each amplitude error
is then stored as a calibration factor.
❏ The center frequency error of each bandwidth is
corrected.
❏ The top-screen reference level is calibrated using
the amplitude of the
CAL OUT signal as a
reference.
1. The amplitude of the detected 21.4 MHz IF
signal is measured on the A16 processor/video
assembly.
2. The Reference-Level-Calibration DAC on the
A7 analog interface assembly adjusts the gain
of the IF Calibration Amplifier on the A9
Third Converter assembly to correct the
amplitude measured on the A16 assembly.
3. After the A7 DAC adjusts the A9 output, fine
amplitude corrections are made with a digital
offset of the video signal on the A16 assembly.
4. The A7 DAC value and video offset are stored
as correction factors on the A16 assembly.
To Next Page
Loading...
