Systems and methods for burst detection in a CATV network
Systems and methods for detecting laser transmission bursts in a CATV network.
1. An active optical combiner comprising:
a plurality of inputs, each capable of receiving an upstream optical signal;
a combiner that combines received upstream optical signals to create a combined signal;
a transmitter that receives the combined signal and converts it to an optical signal at an output;
a controller for the transmitter that monitors the plurality of inputs, and controls the output of the transmitter using received said upstream optical signals,
where the controller includes multiple detectors arranged along a transmission line, where a parasitic capacitance of each detector is inductively matched to a transmission line impedance, and where the transmission line is connected to a first port that puts out an RF signal to an RF amplifier and is connected to a second port via an RF termination resistor having an impedance substantially equal to that of the transmission line; and
the controller further comprising at least one current detection circuit that can detect the presence of photo-current in one or more of the multiple detectors in order to detect the presence of optical power.
2. The active optical combiner of claim 1 including an amplifier that receives at least one of the received said upstream optical signals as an input and outputs an amplified signal to the transmitter.
3. The active optical combiner of claim 2 where the controller controls the output of the transmitter by adjusting a bias of the amplifier.
4. The active optical combiner of claim 1 including a high pass filter between the first port and the RF amplifier.
5. The active optical combiner of claim 4 where the detector circuit includes a trans-impedance amplifier.
6. The active optical combiner of claim 5 where the trans-impedance amplifier is connected to the high pass filter.
7. The active optical combiner of claim 6 including a low pass filter that presents a low impedance, less than the transmission line impedance, at the input to the trans-impedance amplifier.