In a hybrid-code differential analyzer system, variables and parameters are represented by the combination of a coarse n-bit number and a continuously variable analog interpolation voltage. The hybrid-code system combines analog elements accurate to within p per cent of half-scale with the n-bit digital system to form an overall system with greatly improved accuracy within (p/2n) per cent of half-scale. This paper describes a hybrid-code system employing a 5-bit-plus-sign number and an analog channel accurate to within one per cent of analog half-scale. Results of the sine-loop test verify that the predicted theoretical performance is achieved in practice. Further experiments study the performance of the hybrid-code system with a passive RC integrator replacing the active integrator in the analog channel of the hybrid-code integrator. Results of the sine-loop test indicate that sufficient accuracy for practical applications cannot be achieved with a realizable passive RC integrator.
