ACCEPTANCE TESTING
6-41
Envelope control
Specification
Applying 1 V gives the set RF level and 0 V suppresses the carrier.
Linear range
Greater than 30 dB
Linearity
Typically better than 0.5 dB at -20 dB (100 mV input)
On/off ratio
Greater than 80 dB
Envelope delay
Less than 10
μ
s
Rise/fall time
Less than 20
μ
s to -70 dBc
Test equipment
Description Minimum
specification Example
Oscilloscope
100 MHz bandwidth
Tektronix 2235
Spectrum analyzer
80 dB dynamic range at 10 MHz
Aeroflex 2383
Function generator
Square wave capability, DC offset facility
HP3325B
Linearity
(1) Connect the test equipment as shown in Fig. 6-25.
C1669
UUT
RF
OUTPUT
ENVELOPE
IN
INPUT
OUTPUT
➤
➤
2383/2380
Spectrum Analyzer and Display
Function Generator
Fig. 6-25 Linearity test set-up
(2) Set the UUT to a carrier of 10 MHz at 0 dBm in Test Tone Mode with the I and Q amplitude
set to 0 mV and the DC offset set to 500 mV as follows:-
[Carrier Freq.]
10 MHz
[RF Level]
0 dBm [UTIL]
[Mod'n. Mode][Digital]
[SIG GEN]
[Mod'n System][Select Mod. Type][Test Tones][EXIT]
[I Ampli.]
0 mV
[Q Ampli.]
0 mV
[I DC Offset]
500 mV
[SIG GEN]
[Config. Select][External Envelope]