1. Field of the Invention
The present invention relates to a 1 bit/1 bit digital correlator with an independently adjustable integrator reference voltage.
2. Description of the Prior Art
Control loops are required in a number of circuits for demodulation, equalization and regeneration of a quadrature-amplitude-modulated digital signal. Acquisition of the setting voltage for the control elements in such conventional circuits is generally achieved by the use of a correlator which identifies the correlation of two digital bit sequences by means of an exclusive OR circuit and a following integrator stage, the setting voltage being derived from the output of the integrator stage. The performance capability of such demodulation, equalization and regeneration circuits greatly depends upon the precision of the setting voltages. In circuits having a relatively large number of correlators such as, for example, an adaptive basis equalizer, it is a problem in the art to provide a small, simple circuit which generates the setting voltage with optimally high precision, independently of signal scatter, temperature drift and aging characteristics of the components.