Digital Control and Data Acquisition System for the

actuallyabandonedΗλεκτρονική - Συσκευές

15 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Digital Control and Data Acquisition System for the
QUIET Experiment


QUIET (Q/U Imaging ExperimenT ) is meant to characterize the
signature of gravitational waves in the polarization of the cosmic
microwave background. These gravitational waves are thought to
originate from Inflation, the exponentially accelerating expansion of the
very early universe.


QUIET Phase I will operate arrays of 91 4
-
channel W
-
band (90GHz) and
19 4
-
channel Q
-
band (40GHz) polarimeter


receivers, placed on 1.4m
telescopes, in Chajnantor, Chile.



QUIET polarimeters are integrated elements of High Electron Mobility
Transistor (HEMT) RF amplifiers, phase
-
switches, passive phase
discriminators and RF detector diodes.

The polarimeters require biasing
of their monolithic microwave integrated circuits (MMIC), detector diodes,
and phase switches.


QUIET Digital Control and DAQ is responsible for controlling and
monitoring the polarimeter biases, environment monitors and the ADC of
the signal channels.


Mircea Bogdan, Dan Kapner, Dorothea Samtleben, Keith Vanderlinde

7 W
-
band polarimeter modules with
representative optics attached to one.


Cryostat


Functions (Phase I):


Setup and Control of over 1500 current and
voltage bias levels;


Acquisition and real time processing of about
400 analog signals.

Specifications:


DAQ

with

up

to

13

custom
-
made

ADC

boards,

each

with

32

channels

of

18
-
bit,

800
kSPS
.


Digital signals processed with local FPGAs,
demodulated and averaged
over 10ms

intervals.


VME read out at a 100Hz rate.


Full scale input of +/
-
2V;


1 pole input filter


configurable;


Input noise voltage ~ 15uV RMS;


Simultaneous sampling;


Channel
-
to
-
Channel Skew ~ 5ns.

Polarimeters

Bias

Electronics

Master ADC Board

Biases

40 LVDS Communication

Lines

VME Crate

Controller

PC Frontend

VME Backplane

Network

Housekeeping

Electronics

Block Diagram for the QUIET Digital Control System

QUIET Digital Control and DAQ System

Data

Data

Data

Data