To Demodulate The Multi-Path Signal - Agilent Technologies 89410A Operator's Manual

Using Adaptive Equalization (Options AYA and AYH)

To demodulate the multi-path signal

This task shows you how to demodulate the multi-path signal that you
loaded in the previous task.
1.
Load the multi-path signal as instructed in the previous task.
2.
Set demodulation parameters for this signal:
Press [ ], [
Instrument Mode
Press [ ], 5 MHz.
symbol rate
Press [ ], 0.15 [
alpha/BT
Press [ ], [
meas filter root raised cosine
Press [ ], [
ref filter raised cosine
Press [ ], 500 [
result length
Press [ ], [
demod format
Press [ ], [
Time points/symbol
3.
Configure different displays for the demodulated data:
Press [ ], [
4 grids quad
Display
Press ] , [Measurement Data], [
[A
Press [ ], [P10equalizer impulse resp], [
B
P ress [ ], [
C
Mea sure ment Data
Press ] , [
[D
Measurement Data
[ ], [
polar (IQ) constellation
4.
Start the measurement:
Press [ ].
Meas Restart
Traces A and B display the frequency response and the impulse response
of the equalization filter. You can view these displays even when you are
not using the equalization filter. In this example equalization is turned off,
therefore the equalization filter does not change and these displays remain
constant.
Traces C and D display the symbol table and constellation diagram for the
multi-path signal. The signal contains a significant amount of distortion
which makes it difficult to demodulate. The next task uses equalization to
compensate for distortion in the signal which significantly improves these
displays.
By default, the equalization filter is defined to have a unit impulse response
which yields a flat frequency response.
12-4
].
demodulation setup
].
enter
], [ ].
return
], [ ].
return
].
sym
], [ ].
QAM 16 return
enter
], , [ ].
1
].
], [
more choices
], [
Data Format
], [
symbol table/error summary
], [
IQ measured time
], [
more format setup symbol dots
].
channel frequency resp
magnitude log(dB)].
]
], [ ],
Data Format
].