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PC104 Synchro/Resolver Measurement Board

NAI’s 73SD4 is a DSP-based, PC104-compliant Synchro/Resolver Measurement Board with six separate, isolated channels. These channels can incorporate up to six Synchro/Resolver-to-Digital Tracking Converters in a stack-through module. Each channel also produces differential incremental encoder (A & B) outputs (with programmable resolution) and a zero-degree marker pulse. Commutation outputs are available for 4-, 6-, or 8-pole brushless DC motors that eliminate the need for Hall Effect sensors, thereby reducing both processor time and bus traffic.

Standard features include 16 TTL Digital I/O, Background Built-In-Test (BIT) for continuous checking and reporting on the health of each channel, extensive diagnostics, and digital velocity outputs. Specifically designed for rugged defense, commercial aerospace, and industrial applications, the 73SD4 supports optional reference and turn counters. Requires forced air cooling.

  • Six isolated channels for up to six separate Synchro/Resolver-to-Digital Tracking Converters
  • Tracking rate to 150 RPS
  • 16-bit resolution
  • 1 arc-minute accuracy
  • Programmable speed ratios: 1:1 to 255:1
  • Angle change alert
  • Digital velocity output
  • Auto-phase correction
  • Continuous Background Built-In-Test (BIT)
  • Reference-loss, signal-loss, and latch features
  • Programmable bandwidth
  • Optional Hall Effect commutation outputs
  • Optional programmable encoder (A & B) and index outputs
  • Optional on-board reference supply
  • Software Support Kit (SSK) and drivers are available


The 73SD4 includes SSKs to support multiple operating systems. In addition, SSKs are supplied with source code and board-specific library I/O APIs to facilitate system integration.

Accelerate Your Time-to-Mission™ With COSA®

NAI’s Configurable Open Systems Architecture™ (COSA®) offers a choice of over 100 smart I/O, communication, and Ethernet switch functions, providing the highest package density and greatest flexibility of any multifunction I/O board in the industry. Preexisting, fully-tested functions can be combined quickly and easily in an unlimited number of ways. Choose the ideal platform for your application below. Each I/O function has dedicated processing, unburdening the system Single Board Computer (SBC) from unnecessary data management overhead.

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