ACCEPTANCE TESTING
6-33
(14) Check the results ensuring that there are no errors greater than ±1.5 dB at carrier frequencies
up to 2 GHz, or greater than ±2.0 dB at carrier frequencies up to 2.7 GHz (2051T and 2052T
only).
(15) Repeat steps (1) to (18) at an RF level of +6 dBm, resetting the UUT where necessary.
Modulation accuracy
Specification
At the decision points with
the envelope input at 1 V or
disabled:
<1.5% for PSK systems
<1.5% for QAM systems
<1.0% for NADC, PDC (EIA & RCR 27A methods)
Test equipment
Description Minimum
specification Example
Spectrum analyzer
30 kHz to 2.7 GHz freq coverage
Aeroflex 2383
DVM
AC volts measurement to 25 kHz
Datron 1061A
The RMS vector error is measured using DSP-generated test tones and calculated from the RSS of
the following five erors:
1. Carrier
leak
2. Signal
compression
3. I/Q channel balance
4. Channel frequency response errors
5. DSP coding errors (
±
0.3%)
Establishing carrier leak
(1) Connect the test equipment as shown in Fig. 6-13.
(2) Set the UUT to a carrier of 11 MHz, an RF level of 0 dBm, in Digital Modulation Mode with
Test Tones selected and the IQ angle set to 270
°
as follows:-
[Carrier Freq.] 11 MHz [RF Level]
0 dBm [UTIL]
[Mod'n Mode][Digital]
[SIG GEN]
[IQ Selfcal][Mod'n System][Select Mod. Type][Test Tones][EXIT]
[IQ Angle]
270 [enter]
(3) Set the spectrum analyzer as follows:-
Reference frequency
11 MHz
Reference level
10 dBm
Span/div
5
kHz
Video averaging
4 sweeps
(4) Using the markers 1 and 2 facility on the spectrum analyzer, measure the amplitude of the
carrier leak relative to the upper sideband (see Fig. 6-20).