Abstract: Protocol analyzer systems enable synchronization of timestamps and the capture of data across serially chained boxes that are used together to monitor and capture network data. Through experiment, it can be determined how long it takes to propagate a signal to each box in the chain. These values are then recorded in each box in a delay register so that each box has a recorded delay value corresponding to the time required to propagate a signal to or receive a signal from every other box. Each box applies a control signal, such as a run signal or a trigger signal, to the ports in the box only after the expiration of the delay value indicated in the delay register. The box initiating the signal has the largest delay since the other boxes need to get the signal before the boxes can begin to operate with a common counter, with successive boxes having smaller delays.

Abstract: An optical signal return path system analog RF signals are sampled using a master clock frequency, and combined with digital data such as Ethernet data at a cable node. The cable node sends the combined signals on a return path over a fiber optic medium to the cable hub. The cable hub extracts an approximate in-frequency replicate of a master clock signal, and can use the replicate master clock signal to desample the digitized RF signals back to analog. The cable hub can further use the replicate of the master clock signal to serialize Ethernet data, and send the Ethernet data back to the cable node via an optical cable in the forward direction. Accordingly, a single master clock signal can be used on a CATV network for encoding/decoding, and transmitting a variety of data signals, which enhances the integrity and reliability of the data signals.

Abstract: An optical signal return path system includes a transmitter and a receiver. The receiver receives an optical data signal from the transmitter 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 fuller more full than a predefined threshold fullness level. A clock speed adjusting circuit generates the clock control signal in accordance with the fullness signal.

Abstract: A cable node and a cable hub that communicate on a CATV network are configured to switch communication modes without signal loss or degradation due to delays in switching communication modes. In particular, a cable node sends one or more mute commands in an outgoing data stream to the cable hub, causing the cable hub to disable the RF outputs. Afterward, or along with the one or more mute commands, the cable node can send a switch mode command, thereby causing the cable hub to switch to the appropriate next communication mode, such as a communication mode using a new compression rate. When the cable hub has switched to the appropriate next communication mode, the cable hub can then properly receive and decode a corresponding data stream using the next communication mode.

Abstract: A return path transmitter includes an optical signal receiver configured to receive a digital optical signal and generate therefrom a first digitized RF data stream and a sample clock. The return path transmitter further includes 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. The return path transmitter further includes 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. The return path transmitter further includes 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.

Abstract: A cable node and a cable hub that communicate on a CATV network are configured to switch compression modes without signal noise or degradation due to excessive delays in switching compression modes. In particular, a cable node sends one or more mute commands in an outgoing data stream to the cable hub, causing the cable hub to disable the RF outputs. Afterward, or along with the one or more mute commands, the cable node can send a switch mode command, thereby causing the cable hub to switch to the appropriate next communication mode, such as a communication mode using a new compression rate. When the cable node and the cable hub have switched to the appropriate next communication mode, the cable hub can then properly receive a corresponding data stream from the cable node using the next communication mode.

Abstract: The present invention relates to a Cable Television (CATV) that includes a head end with a radio-frequency hub and an Ethernet hub to separately process data transmitted within the CATV. Specifically, the radio-frequency hub receives the data, extracts radio-frequency data therefrom, outputs the extracted radio-frequency data, and transmits the data to the Ethernet hub, which is external to the radio-frequency hub. The Ethernet hub receives the data from the radio-frequency hub, extracts Ethernet data from the data, outputs the extracted Ethernet data to an Ethernet data port, inputs additional Ethernet data from the Ethernet data port, incorporates the additional Ethernet data into the data, and transmits the data, with the additional Ethernet data incorporated therein, to a receiver.

Abstract: The present invention provides for network taps capable of connecting to a plurality of communication cables. The network taps provide one or more levels of multiplexers which allow network data signals from a particular communication cable to be delivered to an attached device in order to monitor the activity of the communication cable. The network taps also include integrated circuitry which control the various functions and components of the network tap.

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.

Abstract: A Cable Television (CATV) digital return link system that provides dedicated, high-speed, full-duplex and point-to-point connections between users and the head end system is disclosed. The CATV digital return link system includes return path transmitters, intermediate hubs and a head end hub coupled to each other via a network of fiber optics cables. The return path transmitters are each coupled to a relatively large number of users via a local CATV-subtree. Signals from cable modems are transmitted via the local CATV-subtree to the return path transmitters for transmission to the head end. A number of users are individually and directly connected to the return path transmitters. Data from these directly connected users is transmitted to the head end via the network of fiber optics cables in conjunction with the RF data from the subtree. Likewise, data from the head end to these directly connected users is transmitted in the forward path direction using the digital return link system.

Abstract: The present invention provides for network taps capable of connecting to a plurality of communication cables. The network taps provide one or more levels of multiplexers which allow network data signals from a particular communication cable to be delivered to an attached device in order to monitor the activity of the communication cable. The network taps also include integrated circuitry which control the various functions and components of the network tap.

Abstract: The present invention relates to a Cable Television (CATV) that includes a head end with a radio-frequency hub and an Ethernet hub to separately process data transmitted within the CATV. Specifically, the radio-frequency hub receives the data, extracts radio-frequency data therefrom, outputs the extracted radio-frequency data, and transmits the data to the Ethernet hub, which is external to the radio-frequency hub. The Ethernet hub receives the data from the radio-frequency hub, extracts Ethernet data from the data, outputs the extracted Ethernet data to an Ethernet data port, inputs additional Ethernet data from the Ethernet data port, incorporates the additional Ethernet data into the data, and transmits the data, with the additional Ethernet data incorporated therein, to a receiver.

Abstract: A Cable Television (CATV) digital return link system that provides dedicated, high-speed, full-duplex and point-to-point connections between users and the head end system is disclosed. The CATV digital return link system includes return path transmitters, intermediate hubs and a head end hub coupled to each other via a network of fiber optics cables. The return path transmitters are each coupled to a relatively large number of users via a local CATV-subtree. Signals from cable modems are transmitted via the local CATV-subtree to the return path transmitters for transmission to the head end. A number of users are individually and directly connected to the return path transmitters. Data from these directly connected users is transmitted to the head end via the network of fiber optics cables in conjunction with the RF data from the subtree. Likewise, data from the head end to these directly connected users is transmitted in the forward path direction using the digital return link system.

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.