ACCEPTANCE TESTING
6-42
(3) Set the spectrum analyzer as follows:
Reference frequency
10 MHz
Reference level
10 dBm
Span/div
5
kHz
(4) Set the function generator to give 1 V DC (into high impedance).
(5) Select Peak Find on the spectrum analyzer and record the marker 1 level:
Marker 1 level = __________ dBm
(6) Set the function generator to give 0.1 V DC (into high impedance).
(7) Record the marker 1 level:
Marker 1 level = ___________ dBm
The difference between this value and that recorded in step (5) above should be 20
±
0.5 dBm.
On/off ratio
(8) Set the spectrum analyzer as follows:-
Reference level
−
10 dBm
(9) Disconnect the envelope input from the UUT and apply a short circuit.
(10) Record the marker 1 level:
Marker 1 level = ____________ dBm
The difference between this value and that recorded in step (5) above must be greater than 80 dB.
Envelope delay
(11) Connect the test equipment shown in Fig. 6-26.
C1671
UUT
RF
OUTPUT
CH 1
CH 2
50
Ω
THROUGH
LOAD
ENVELOPE
IN
OUTPUT
Function Generator
Oscilloscope
Fig. 6-26 Envelope delay test set-up
(12) Set the function generator to give 1 V pk with 0.5 V DC offset (into high impedance) square
wave at 10 kHz.
(13) Set the UUT as follows:
[SIG GEN]
[Mod’n System]
[I Ampli.]
500 mV
[Q Ampli.]
500 mV
[I DC Offset]
0 mV
(14) Set the oscilloscope CH1 sensitivity to 0.5 V/div, the CH2 sensitivity to 0.1 V/div, both
traces, timebase 2
μ
s/div.
(15) Check that the delay from the transitions of the function generator output to the 50% point of
the corresponding transitions of the UUT RF level is less than 10
μ
s.
(16) Viewing CH2 only on the oscilloscope, measure the rise and fall times (the time of the
transition between 10% and 90% of the high and low RF levels) ensuring that they are less
than 13.5
μ
s. This includes a 6.5
μ
s allowance for the difference between the 10/90% and the
0/70 dB rise-times.