Abstract: A process of determining the Eb/No ratio of a digital transmission is applied to a signal having a plurality of phases made up of two data streams in phase quadrature providing in each symbol time a received sample whose position in the constellation is defined by its coordinates obtained by quantizing the data streams. This process determines the number of erroneous samples received during a given time period whose coordinates correspond to those of indicative samples, the coordinates of the indicative samples being different from those of optimal samples received under optimal transmission conditions. The process then calculates the ratio between the number of erroneous samples and the total number of samples received in this time period, the calculated ratio being inversely proportional to the Eb/No ratio.

Abstract: A method of controlling a digital carrier recovery apparatus designed to be integrated in a demodulation stage of a receiver for receiving a digital signal. The demodulation stage includes a carrier recovery detection apparatus. The carrier recovery detection apparatus includes a loop filter including a summing circuit followed by a bistable circuit operating in time with the symbol time, and a switching device disposed between the summing circuit and the bistable circuit. The switching device is driven to alternately apply to the bistable circuit a control word, whose variation between two successive applications to the bistable circuit is less than the acquisition band of the carrier recovery apparatus, and the output signal of the summing circuit. By alternately applying the control word and the output signal, the acquisition band is displaced relative to the tracking range of the carrier recovery apparatus.