METHOD AND APPARATUS FOR TRANSMITTING BROADBAND AMPLITUDE MODULATED RADIO FREQUENCY SIGNALS OVER OPTICAL LINKS

A plurality of radio frequency channels are separated into two or more contiguous groups of channels, each of such groups occupying less than one octave. A first group of channels occupies a 54 MHz to 106 MHz band, a second band of channels occupies a 108 MHz to 214 MHz band, and optionally, additional channel groups may occupy the bands of 214 MHz through 426 MHz and 426 MHz through 850 MHz. Each sub-band is used to modulate the intensity of the output of a laser (1, 2, 3). Each resulting amplitude modulated light signal is transmitted over an optical link (F1, F2, F3, F4) to a receiving location. Alternatively, the lasers (1, 2, 3) may be selected to generate light at different wavelengths with all outputs transmitted over a single optical link. At the receiving location, each of the optical signals is received and demodulated by a respective individual receiver (51, 52, 53). The demodulated signal is passed through a bandpass filter which reduces harmonics, intermodulation distortions, and noise produced in transmission. The resulting signals are then matched in amplitude before being applied to combiner (69, 70) which converts them back into a single broadband signal. The broadband signal is then processed to reduce discontinuities at the transitions between the sub-bands. All of the baseband television signals can be modulated onto carrier frequencies in the highest sub-band of interest (e.g., in the range of 330 to 550 MHz). Because of the separation of signals provided by multiple optical links (F1, F2, F3, F4), the same carrier frequency may be utilized on each of the links to carry a channel of baseband video information.