4-5.
MAXIMUM LEVELED OUTPUT POWER AND POWER ACCURACY
TEST (Cont’d)
Description
MAXIMUM LEVELED POWER
For maximum leveled power, a crystal detector and an oscilloscope are used to monitor the swept
response. The DUT is set to sweep a given frequency band. The power level is increased until the
DUT’s UNLEVELED indicator comes on, then decreased until the UNLEVELED indicator just goes
out. The maximum leveled power may differ with sweep mode and sweep time. To find the worst case,
the maximum leveled power is checked in three modes: single sweep with auto sweep time, single
sweep with a two second sweep time, and continuous sweep. The worst case mode is selected, and a
frequency marker is positioned at the minimum power point on the swept display. The DUT is set to
CW at the marker frequency and the power is measured using a power meter. The power meter
indication should be greater than or equal to the maximum leveled power specification. This pro-
cedure is repeated for each frequency band.
FLATNESS
Flatness is measured with the RF output level at 0 dBm. Flatness is primarily a function of the RF path;
therefore, the response will be essentially the same at all ALC levels. However, the response will most
likely change when the RF Attenuator is stepped to a different attenuation level.
A power meter is used to measure the RF signal level. An oscilloscope, connected to the power meter
recorder output, is used to find the frequencies where the maximum and minimum points of the
response occur. The DUT is set to a slow sweep to allow the power meter to respond to any power
variations. A marker is positioned at the maximum and minimum points on the oscilloscope display.
The DUT is then set to CW at each of the marker frequencies and the power indications are recorded.
The maximum power level minus the minimum power level should be within the flatness specification.
ACCURACY
The absolute power level at the maximum and minimum points should be within the accuracy specifi-
cation.
Two different Power Sensors may be required to cover the complete frequency range. The HP 8481A
Power Sensor is used from 10 MHz to 50 MHz and the HP 8485A Power Sensor is used for the other
frequency bands covering 50 MHz to maximum output frequency of the DUT. The 8485A Power
Sensor can be used down to 10 MHz, but if a minimum or maximum that is close to the test limits
occurs in this frequency range, the 8481A Power Sensor should be used.
Equipment
Oscilloscope
HP 1741A
Attenuator
HP 8493C Opt.
010
Crystal Detector
HP 8473C
Power Meter
HP 436A Option 022
Power Sensor
HP 8481A
Power Sensor
HP 8485A
Adapters
APC 3.S (f)
to
APC
3.5
(f)
HP P/N 5061 -5311
(1 required if DUT is HP 8340B)
TYPE N (in) to APC 3.S (f)
HP P/N 1250-1 744
(1
required if
DUT
is HP 8341 B)
SMC (f)
to
BNC (f)
HP P/N 12S0-0832
HP 8340B/41B
Performance Tests
4-27
