| 摘要 |
<p>The field of the invention is that of the demodulation of digital signals modulated by frequency-shift keying (FSK). The invention applies in particular to radio telephony. The invention relates to a device for demodulating a digital signal modulated by frequency-shift keying, a distinct modulating frequency (f1,f2) being assigned to each digital value which the digital signal may take, the device being of the type comprising means for converting the received modulated signal into a logic signal (FSKR) capable of taking two distinct values, comprising means for measuring the times elapsed between two successive rising edges (13M) and between two successive falling edges (13D) of the said logic signal (FSKR), cooperating with means (14) for analysing the said elapsed times, delivering an estimation of the value of the said digital signal, updated with each detection of one of the said rising and falling edges of the said logic signal (FSKR). In this way, all the transitions of the received signal are taken into account. The decision time for the value of the demodulated digital signal is therefore faster. Moreover, the accuracy in regard to the value of this demodulated signal is enhanced: its value is updated each half-period. <IMAGE></p> |
