logosmallarcetri Arcetri Technical Reports 4/2002


Atacama Large Millimiter Array
Demultiplexer design based on a custom GaAs chip

G. Collodi(1 2), G. Comoretto(2)

(1) Mecsa - Dipartimento di Elettronica e Telecomunicazioni
(2) INAF - Arcetri Astrophysical  Observatory

Abstract

In the ALMA sampler the input data, sampled at 4 Gs/s, is transmitted to the fiber optic formatter in a parallel demultiplexed data stream composed of 16 x 250 MHz samples. Several different approaches have been proposed for the demultiplexer, as no commercial units are available at this frequency. We propose a scheme based on a custom digital GaAs chip. The chip architecture, the global demultiplexer architecture and results from simulations are presented.

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