Keysight 81150A - Noise Generation

Appendix
620
7.5 Noise Generation
Introduction
The Keysight 81150A / 81160A generates noise waveforms using a digital
noise source.
This digital noise source consists of the following four major blocks:
 Address Generation
 Sample Memory
 Digital Filter
 Digital Analog Converter
The block diagram is very similar to a traditional memory based noise
generation, but there is one crucial difference: the sample memory holds a
sample distribution, rather than pre-calculated samples. The sample memory
is read using a random address generator.
Random
Address
Generation
Memory
Address
Compression
Sample
Memory
Digital
Filter
(FIR)
Waveform
DAC
Virtual Address
(46 bits)
Address
(19 bits)
Data
Noise with Memory Address Compression
The advantage of this approach is that the voltage domain is separated from
the time domain. The memory content determines the distribution of the
output signal, while the address generation determines the repetition rate
and randomness of the output signal.
Due to the huge virtual address range, the generated noise signal repeats
after approximately 26 days.