Bird Technologies VPM3 - Manual (Page 30)

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User Manual
Opens a html version of the user manual.
About Virtual Power Meter
Displays version info about the VPM and any attached sensors.
About Sensor
Displays model information of the selected sensor.
Menu Label Keys
Configure
Note: Specific configuration features depend upon the power sensor
being used.
When the Configure menu key is pressed, the soft key functions that specify the
setup information about the sensor and the measurements are enabled. What
type of element in the power sensor, offsets for input and match, duty cycle,
and the scale for forward and reflected power is displayed at this time.
Note:
For DPS sensors, element scales have pre-defined values and
an “Other” category for arbitrary values.
Note:
The 5015-EF offset factors are used for frequencies above 4
GHz.
For Wide Band Power Sensors
Video Filter -
Except for average power and VSWR measurements, all WPS
measurements rely on a variable video filter to improve accuracy. This filter can
be set to either 4.5
kHz, 400 kHz, or full bandwidth. It should be as narrow as
possible while still being larger than the demodulated signal bandwidth (video
bandwidth). Narrowing the filter limits the noise contribution caused by inter-
fering signals. Listed below are some common modulation schemes and the
appropriate video filter.
Video Filter Modulation Type
4.5 kHz CW Burst (Burst width > 150 μs), Voice Band AM, FM, Phase
Modulation, Tetra
400 kHz CW Burst (b.w. > 3 μs), GSM, 50 kHz AM, DQPSK
Full Bandwidth CW Burst (b.w. > 200 ns), CDMA, WCDMA, DQPSK, DAB/DVB-T
Note:
7022 has 5KHz, 500KHz, and 5MHz VBW filter and only effects
the time domain data, not average power.
Figure 16 Video Filter Settings, 300 kHz Signal