User Manual - TRS-RenTelco

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Type N to BNC adapter (Qty 2)
75 Ω BNC female/female adapter
50 Ω BNC female/female adapter
1. Connect the MIU to the VM5000, apply power, and establish communications
using Hyperterminal as described in Test A of this procedure.
2. Check that the MIU RGB WB Path LED is lit. If not, using Hyperterminal,
send the command $LOAD=1000000 to the MIU. Verify that the RGB WB
Path LED is illuminated.
3. On the VM5000 front panel, under VERTICAL, select 50 Ω for CH1, CH2,
and CH3.
4. Set the tracking generator and spectrum analyzer controls as follows:
Tracking Generator output level = 0 dBm
Spectrum Analyzer Vertical scale = 1 dB/div
Spectrum Analyzer Reference Level = -10 dBm
Horizontal scale (Span) = Max Span (or 200 MHz/div if available)
Center Frequency = 900 -1000 MHz (10 div display)
Resolution BW (RBW) = 3 MHz
5. Connect a Type N to BNC adapter, followed by a 6 dB attenuator, to the
tracking generator output. Connect a 50 Ω BNC cable to the other end of the
attenuator. Connect a second Type N to BNC adapter and 6 dB attenuator to
the spectrum analyzer input, and connect the other end of this attenuator to a
second 50 Ω BNC cable. Connect the two cables together with a 50 Ω BNC
female/female adapter.
6. Adjust the analyzer Reference Level control until the displayed signal is
entirely on screen over the frequency range 1 MHz to 1800 MHz.
7. Using the analyzer Display memory, store the swept display. Activate the
“active display minus stored display” mode (sometimes called “B minus
Save A”). A straight line display, with less than 0.2 dB ripple, should appear,
typically at mid-screen. This is the frequency response with the flatness
errors of the tracking generator, attenuators, spectrum analyzer, and cables
normalized out.
8. Connect two 75/50 min-loss pads together, using a 75 Ω BNC female/female
adapter. Insert this connection in place of the 50 Ω BNC female/female
adapter. Decrease the analyzer Reference Level by 11 dB, so that the
frequency response of the series connected min-loss pads can be observed.
Measure the response at 1500 MHz, relative to 1 MHz, and record this value
16 VM5000 Automatic Video Measurement Set Option VGA Read This First