SYSTEM AND METHOD FOR TRANSMITTING DATA ON RETURN PATH OF A CABLE TELEVISION SYSTEM
First Claim
1. A return path transmitter for use in conjunction with a local system that generates an analog RF data signal to be conveyed to a head end system, the return path transmitter comprising:
- an optical signal receiver configured to receive a digital optical signal and generate therefrom a first digitized RF data stream and a sample clock;
an RF signal receiver, coupled to the optical signal receiver, configured to receive and convert the analog RF data signal into a second digitized RF data stream of digitized RF data samples at a rate determined by the sample clock;
a summing circuit configured to mathematically sum the first and second digitized RF data streams so as to generate a third digitized RF data stream; and
an optical transmitter configured to convert an output data stream into a serialized optical data signal for transmission over an optical fiber, the output data stream including the third digitized RF data stream.
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Accused Products
Abstract
An optical signal return path system includes a transmitter having a sample clock generator for generating a sample clock and an RF signal receiver for receiving and converting an analog RF data signal into a first data stream of digitized RF data samples at a rate determined by the sample clock. Supplemental channel circuitry provides a second data stream. A multiplexor receives and combines the first data stream and second data stream, and an optical transmitter converting the combined data stream into a serialized optical data signal for transmission over an optical fiber. The second data stream may contain maintenance data reflecting an operational state of the transmitter. A receiver receives the optical data signal and recovers therefrom a digital data stream and an associated first clock having an associated first clock rate. The data stream is stored in a memory device at the first clock rate. A clock generator generates a second clock having an associated second clock rate that is adjusted in accordance with a clock control signal. A control circuit reads data from the memory device at a rate corresponding to the second clock rate and generates a fullness signal that indicates whether the memory device is more full than a predefined threshold fullness level. A clock speed adjusting circuit generates the clock control signal in accordance with the fullness signal.
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Citations
4 Claims
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1. A return path transmitter for use in conjunction with a local system that generates an analog RF data signal to be conveyed to a head end system, the return path transmitter comprising:
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an optical signal receiver configured to receive a digital optical signal and generate therefrom a first digitized RF data stream and a sample clock;
an RF signal receiver, coupled to the optical signal receiver, configured to receive and convert the analog RF data signal into a second digitized RF data stream of digitized RF data samples at a rate determined by the sample clock;
a summing circuit configured to mathematically sum the first and second digitized RF data streams so as to generate a third digitized RF data stream; and
an optical transmitter configured to convert an output data stream into a serialized optical data signal for transmission over an optical fiber, the output data stream including the third digitized RF data stream. - View Dependent Claims (2)
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3. A method for transmitting data representing an analog RF signal generated at a local system, the method comprising:
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receiving a digital optical signal and generating therefrom a first digitized RF data stream and a sample clock having an associated sample rate;
receiving and converting the analog RF signal into a second digitized RF data stream of digitized RF data samples at a rate determined by the sample clock;
mathematically summing the first and second digitized RF data streams so as to generate a third digitized RF data stream; and
converting an output data stream into a serialized optical data signal for transmission over an optical fiber, the output data stream including the third digitized RF data stream. - View Dependent Claims (4)
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Specification