HP 5355A - Page 29

Model 5355A
Operation and Programming
shifting of the decimal point. The
key adds two digits to the display each time it is
pressed for a total of 10 decimal places.
GHz to MHz, kHz, Hz, mHz, and ^uHz.
3-21. When the offset frequency has been selected as described in the preceding paragraph.
^ key changes the display annunciators from
press and release the
OFFSET
FREQ
LOCAL
key to depart the DATA ENTRY mode and press
key
to enter the OFFSET mode.
3-22. Remote Programming Mode
3-23. The 5355A is remotely controlled via internal interface circuits and a rear panel connector
to the Hewlett-Packard Interface Bus (HP-IB). The 5355A operates in the Listen Only mode.
Remote programming is described in detail in paragraph 3-58.
3-24. The REMOTE indicator on the front panel, when illuminated, indicates the 5355A is under
remote operation and all front panel controls are inoperative, except fTlieQ pushbutton
(unless the Local Lockout command has been sent).
3-25. The LISTENING indicator on the front panel, when illuminated, indicates the 5355A is
addressed and monitoring the interface bus.
3-26. AM Tolerance
3-27. The 5355A/5345A will measure carrier frequencies containing amplitude modulation to
any modulation index provided the minimum voltage of the signal is greater than the sensitivity
specification of the 5355A.
3-28. FM Tolerance
3-29. The 5355A/5345A will measure carrier frequencies which are modulated in frequency
such as a microwave radio carrier. The FM tolerance is the worst case FM deviation which can be
present without affecting the counters ability to acquire the signal. If the deviations about the
carrier are symmetrical, then the counter averages out the deviations to measure the actual
carrier frequency. The FM tolerance is determined by the mode of operation. See Table 1-1. The
auto mode provides FM tolerance of 15 MHz peak-to-peak. A special FM mode is selected by
pressing
and
simultaneously (in CW auto mode). The special FM mode
provides a tolerance of 60 MHz peak-to-peak but results in slower acquisition time (1.1 second
compared to 400 milliseconds for CW position).
NOTE
Most measurements should be made without using the special
FM mode. The special FM mode should be used only when the
input signal has significant amounts of FM (>15 MHz p-p).
3-30. Automatic Amplitude Discrimination (CW Mode)
3-31. The automatic amplitude discrimination feature allows the 5355A to acquire and display
the highest level signal within its sensitivity range. The highest level signal must be8dB greater in
amplitude than any other signal present within 500 MHz and 20 dB greater than any signal over
the full range. This feature is useful for discriminating against spurious signals and harmonics.
3-7