Keysight 1158 Series, Руководство по эксплуатации и обслуживанию, Страница: 21 / 31

Keysight 849x and 1158x Operating and Service Manual 21
Operating Instruction
Operator’s check
The operator's check is supplied to allow the operator to make a quick check of the attenuators
prior to use or if a failure is suspected.
Using oscillator and SWR meter
Description
The attenuator is driven from a 50-ohm signal source at 1 kHz. The output level from the
attenuator is detected by a narrow-bandwidth voltmeter (that is, the SWR meter). A reference level
is set up on the detector using a through connection in place of the attenuator. The attenuator is
then inserted and the change in the detector level is noted. This checks the low frequency
accuracy of the attenuator.
Quick-check procedure
1 Connect the equipment as shown in the Figure 1 except remove the attenuator and connect the
adapters directly together.
Figure 1 Equipment setup using oscillator and SWR meter
1 Set the test oscillator to 0.3 Vrms at 1 kHz.
2 Set the SWR meter range to 2 dB (expanded) or for the 3 dB, 6 dB, and 10 dB (expanded) as
appropriate and adjust its bandwidth to the center of the adjustment range. Fine tune the
oscillator frequency to obtain maximum meter indication. Adjust the oscillator output to obtain
the SWR meter reading in the table below.
3 Connect the attenuator into the system, adjust the SWR meter range switch as listed in
Table 11 , and verify that the SWR meter indicates within the limits as shown Table 11 .
NOTE
The SWR meter used in this check is calibrated for a square-law detector and therefore the range
changes and errors (read in dB) are twice that indicated by the meter.