81199A Datasheet, PDF (3/17 Pages) Keysight Technologies – Wideband Waveform Center

03 | Keysight | 81195A Optical Modulation Generator Software - Data Sheet
Waveform Creation Methods
The 81195A software provides two means of generating waveforms. As shown in the
figure below, waveform mode creates them using software algorithms. Real-time mode
uses the M8195A hardware DSP block to create the waveforms.
Waveform mode
Calculates data
(e.g. PRBS)
Calculates encoding,
pulse shaping, optical
signal properties
81195A software
Memory
(contains waveforms)
DAC
Ix
DAC
Qx
DSP engine (encoding,
pulse shaping, optical
DAC
Iy
signal properties)
DAC
Qy
M8195A arbitrary waveform generator
Real-time mode
Calculates data
(e.g. PRBS)
Calculates encoding,
pulse shaping, optical
signal properties
81195A software
Memory
(contains symbols)
DAC
Ix
DAC
Qx
DSP engine (encoding,
pulse shaping, optical
signal properties)
DAC
Iy
DAC
Qy
M8195A arbitrary waveform generator
Each method has distinct benefits:
–  In waveform mode
–– A wide range of baud rates are available (real-time mode is limited to certain
ranges)
–– Signal waveforms with non-integer number of samples per symbol can be
generated using waveform resampling
–  In real-time mode
–– Signal properties like pulse shaping parameters and signal impairments can be
modified at run-time without need for re-calculating and re-downloading a new
waveform, significantly reducing test time
–– Real-time operation allows signal property generation and variation, such as
polarization rotation, either as fast transients or slowly changing effects over a
long period of time
–– Trigger output, which is aligned with the signal impairment pattern, can be used to
synchronize test equipment, e.g. time-to-error measurement with BERT