To Create An Ideal Digitally Modulated Signal - Agilent Technologies 89410A Operator's Manual

Creating User-defined Signals (Options AYA and AYH)

To create an ideal digitally modulated signal

You may create a digitally modulated signal by using noise as the input and
saving the reference signal of your selected demodulation format. You may
check the created signal by playing it through the source as shown in the
following task. This example creates a 32QAM signal but most digitally
modulated signal types may be created in a similar way (see text on
following page). The waveform created by the following procedure is
included on the Signals Disk as "32QAM.DAT".
This task uses digital demodulation. If you want to perform this task using
video demodulation, choose video demodulation instead of digital
demodulation in step 3.
1.
Initialize the analyzer:
Press [ ], [
Instrument Mode
89410A: [
input section (0-10 MHz)
89441A: [
RF section (0-10 MHz)
Press [ ].
Preset
Press [
Instrument Mode
2.
Select a center frequency and span:
Press [ ], [
center
Frequency
Press [ ], 61, [
span kHz
3.
Select a digital demodulation format:
Press [
Instrument Mode
[ ], [
Instrument Mode demod type
Press
[demodulation setup
Pre ss [ ], [
demod format
4.
Select demodulation format parameters:
Press [ ], [
Return symbol rate
Press [ ], 240, [
result length
Press [ ], [
ref filter root raised cosine
Pres s [ ], [
Return alpha / BT
Press [ ], [
more normalization
Press [ ], [
Time points/symbol
Press [
], [
pulse search off
5.
Select a reference time display (the Data Format is irrelevant):
Press [
Measurement Data
Press [ ], [
Data Format
Press [ ].
Auto Scale
6.
Save the signal to a register:
Press [ ], [
Save/Recall
7.
You may want to the save the created signal to a disc for more permanent
storage:
Press [ ], [
Save Recall save trace
11 - 2
], then press:
receiver
].
].
], [ ].
vector
], 5, [ ]
MHz
].
], [ ] (with option AYH, press
Digital Demodulation
], [ ], [
Digital Demodulation
].
].
QAM 32
], 30.5, [ ],
kHz
]
sym
]
], .5, [ ]
enter
on].
], 5, [ ],
enter
].
sync search off
], [ ]
IQ reference time
]
polar (IQ) constellation
], [ ].
save trace into D1
], [ ], and enter a file name.
into file
).
Return]