ACCEPTANCE TESTING
6-38
Vector modulation mode
Specification
Vector input impedance
Selectable between 50
Ω
and 300
Ω
.
DC vector accuracy
For carrier frequencies up to 2 GHz:
±1% amplitude of full scale,
±1° at full scale.
For carrier frequencies above 2 GHz:
±1.5% amplitude of full scale,
±1.5° at full scale.
Vector bandwidth
±0.5 dB wrt DC for frequencies up to 3 MHz,
±1 dB wrt DC for frequencies up to 10 MHz.
Carrier suppression
Typically 50 dB at 10 kHz rate.
SSB image suppression
Typically 50 dB at 10 kHz rate,
typically 50 dB at 1 MHz rate,
typically 45 dB at 3 MHz rate,
typically 38 dB at 10 MHz rate.
Test equipment
Description Minimum
specification Example
Digital voltmeter
(DVM)
Resistance measurement capability
Datron 1061A
Spectrum analyzer
30 kHz to 2.7 GHz freq coverage,
60 dB dynamic range
Aeroflex 2383
Function generator
DC to 10 MHz sine wave,
±0.2 dB flatness to 1 MHz,
±0.6 dB flatness to 10 MHz.
HP3325B
Vector input impedance
(1) Connect the test equipment as shown in Fig. 6-23 above.
(2) Set the UUT as follows:
[UTIL]
[Mod'n Mode][Vector]
[SIG GEN]
With the DVM set to measure resistance, check for a reading of approximately 50
Ω
.
(3) Set the UUT IQ input impedance to 300
Ω
using
[Config Select][IQ I/P''Z'']
.
(4) Check for a reading on the DVM of approximately 300
Ω
.
(5) Repeat steps (2) to (5) for the UUT Q input. (Ensure that the input impedance is returned to
50
Ω
by using
[IQ I/P ''Z'']
.)
DC vector accuracy
The RMS vector error is calculated from the RSS of the following three errors:
1. Carrier
leak*
2. Signal
compression
3. Channel
balance*
* These figures are copied from the 'Digital modulation mode', 'Modulation accuracy test', results
derived on page 6-33 and 6-35 in steps (4) and (10) respectively.