| 摘要 |
In a digital optical transmission system, such as a passive optical distribution network, analog electric signals, e.g., video signals, are to be optically transmitted in such a way that they can be recovered in a receiver (BONT) in a simple manner. To accomplish this, the transmitter of the transmission system includes a delta-sigma modulator (MOD) and an electrical-to-optical transducer (EO). The delta-sigma modulator (MOD) digitizes the analog electric signals using the delta-sigma modulation method. The electrical-to-optical transducer (EO) then converts the digitized signals to optical signals, which are transmitted over optical fibers to a plurality of receivers (BONT). To recover the analog electric signals, each receiver (BONT) requires only one optical-to-electrical transducer (OE) and one passive electric filter (FIL). The filter (FIL) is a passive low-pass filter in one case and a passive bandpass filter in another. Appropriate selection of the sampling frequency for the delta-sigma modulation and utilization of image frequencies for transmission eliminate the need for frequency translators in the receivers (BONT).
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