I.                   BACKGROUND INFORMATION

The Communications Technology Laboratory (CTL) requires a receiver system that can coherently sample multiple channels that have been coherently down converted from a higher frequency and sampled at baseband.  This receiver system will be used to sample modulated fields with metrology grade accuracy.  Target signals to measure are radar pulses, wideband and time coherent communication transactions, sparse signals from phased arrays, and reference wideband standard modulated fields.  The receiver system will additionally be able to synchronously sample baseband and IF frequency data so analysis of propagation through the equipment can be determined.

II.                SCOPE OF WORK

There are two major portions of the system that must work together.  Section 1 is the downconverter section and section 2 is the sampler section.  The downconverter will use a common Local-Oscillator (LO) to provide at least 4 channels of coherent frequency conversion with up to a 3.5 GHz instantaneous bandwidth centered at a user defined frequency between 10 MHz and 40 GHz.  The sampler will be at least 8 sampling channels of 1.5 GHz bandwidth data.  To match the output range of the downconverter section, a gain stage is necessary to amplify the downconverter output to better match the input range of the sampler channels.  To coordinate sampling frequency of the digitizers with the LO reference for the down-conversion process, both sections 1 and 2 will have a common frequency reference.

Critical Specifications:

Down Converter:

·         10 MHz to 40 GHz operation

·         Common thermal base for all mixers

·         Conversion efficiency (outlined below)

·         4 channel minimum

Sampler:

·         Channel to channel differential phase skew and time skew (outlined below)

·         Dynamic range

·         Sampler bandwidth