General; Description - Promax OP-170-E Manual De Instrucciones

OP-170-E USER'S MANUAL
White Noise & Echoes Generator

1 GENERAL

1.1 Description

This appendix contains the operating instructions for the following option
belonging to the COFDM modulator: MO-170
OP-170-E White noise generator for C/N testing. Fixed and portable channel
simulation in SFN/MFN networks.
The MO-170 is a versatile professional DVB-T modulator providing a complete
test suite, which can be used to perform measurements on the DVB-T signal chain at
different points. In addition to the test modes typically found in other equipment, the
MO-170 includes other novel features, such as the addition of white Gaussian noise
with selectable C/N ratio and the simulation of fixed and mobile multipath
channels with up to 6 taps of variable amplitude, delay, phase and Doppler
frequency.
In the MO-170, white Gaussian noise with twice the bandwidth of the DVB-T
signal is digitally added to the COFDM signal. Both the C/N ratio and the RF signal
level (COFDM and noise combined) can be varied. This provides the means to either
keep the signal power constant whilst varying the C/N (e.g. to plot the BER vs. C/N
ratio of a demodulator), or to keep the C/N ratio constant whilst varying the signal
power (e.g. to find the sensitivity of a receiver). In addition, the DVB-T signal may be
switched off while the noise is still on, and vice versa. This way, noise and signal
average powers can be measured externally using the appropriate equipment so as to
verify the selected C/N ratio reading. The fact that both noise and signal are digitally
synthesised has the added benefit of generating C/Ns with a precision difficult to
achieve in a traditional assorted test set-up.
The MO-170 offers the possibility of simulating dynamic and static multipath
channels with five echoes (plus the main path).
(1) Trade Mark of the DVB Digital Video Broadcasting Project (4026)
06/2006
OP-170-E
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