Correlation Spectrometer

The existing correlator is largely under manual control with a few limited functions under computer control via the DIO on the HP 1000.

The functions under computer control which must be reproduced in the NCCS are :

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start correlator (output)

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read data ready signal (input)

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read 16-bit parallel data from the correlator (input),

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``fix'' data as is done by ACFIN program on HP 1000 (to produce an auto- or cross-correlation function)

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transmit correlator data (raw and/or fixed) to master computer and convert correlation function to spectrum.

These functions are presently implemented via a dedicated interface consisting of 2 control lines and 16 data lines.

The new correlator interface will be based on a PC. It will look like a black box to the master computer and will be interfaced via Ethernet or RS-422 or HPIB.

In addition to the above mandatory commands the new system should accept the following commands (cf. A Proposed Configuration for the New Control Computer System (NCSS)) :

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select video signal bandwidth,

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select correlator bandwidth,

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set video signal level via computer-controlled attenuators,

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reset correlator,

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set most significant bits of the correlator count (i.e. replace thumbwheel switches),

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setup correlator quadrant configuration,