R&S AFQ100A
Feature Summary
1401.3078.62 2.3
E-3
Feature Summary
The instrument's main features are:
The system clock frequency f
system
amounts to 300 MHz, thus processing a large amount of digital
data per second. The maximum resolution of the I and the Q signals is 16 bits each.
During signal processing, the clock frequency is converted from the symbol rate f
symbol
of the
incoming signal to the instrument’s system rate f
system
which amounts to 300 MHz, i.e., digital
signals are resampled in real time. This saves memory space because the data need not to be
calculated and saves using a greater symbol rate than desired. The symbol rate may vary from
1 kHz to 300 MHz, the latter figure is the clock frequency at which the signal is calculated in the
external control computer processing the digital baseband signal.
The sample memory size amounts to 256 MS or 1 GS, the numerical values apply to instrument
version B10 or B11, respectively.
The accessible RF bandwidth amounts to 200 MHz, which corresponds to an I and Q bandwidth of
100 MHz each. This large bandwidth applies to forthcoming RF standards, e. g. future WLANs. RF
modulation could be done by a separate instrument, e.g. the R&S SMU Vector Signal Generator.
The overall frequency response of the modulation generator is smoothed, using correction filters
which compensate deviations of the analog I/Q output’s low pass filter. The frequency response
varies within an interval of 0.05 dB even if the whole I/Q bandwidth of 100 MHz is used.
The client may use his own RF generator, in this case, the frequency response of its input amplifier
and its RF modulator has to be accounted for and can be corrected without modifying baseband
processing done by the control PC. The modulation generator also compensates phase
mismatches.
The user can intentionally apply impairments which will result in greater bit error rates: I and Q path
delay, I and Q attenuation, I and Q voltage offset and the relative phase error.
The Spurious Free Dynamic Range (SFDR) of a signal whose bandwidth is 1 MHz amounts to
-80 decibels below carrier (dBc). The SFDR indicates the logarithmic power ratio of a converted
main signal and the greatest undesired one.
Exact skew adjustment to account for different cable lengths in the analog section, and, hence,
signal propagation times of 10 ps resolution, are possible.
The instrument loads multi segment waveform files, thus very fast switching from one waveform to
another without loading a new file is possible.
