Transport packet rate conversion

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate;
• a source of additional packets;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream wherein the control signal source comprises:
• an accumulator for generating a signal having a value representing the time the input packet stream is in advance of the output packet stream;
• and
• a comparator for comparing the accumulator output signal to a signal representing an output packet time duration, and if the value represented by the accumulator output signal is less than the value representing an output packet time duration, generating the control signal having the first state, and if the value represented by the accumulator output signal is greater than the value representing an output packet time duration, generating the control signal having the second state;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate;
• a source of additional packets;
• a source of an output packet clock signal indicating when an output packet is to be inserted into the output packet stream;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state wherein the multiplexer controller further samples the control signal in response to the output packet clock signal and conditions the multiplexer to insert an input transport packet into the output packet stream in response to the output packet clock signal when the sampled control signal has the first state, and an additional packet into the output packet stream in response to the output packet clock signal when the sampled control signal has the second state.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate;
• a source of additional packets;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream wherein the control signal source comprises a variable duty cycle oscillator generating the control signal having a duty cycle having an ‘on’ time representing the fraction of the time input transport packets should be inserted into the output packet stream, and an off time representing the fraction of the time additional packets should be inserted into the packet stream;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate wherein:
• the second rate is equal to the first rate;
• the input transport packet stream contains null packets;
• and
• the input transport packet stream source comprises an input packet buffer, generating a status signal indicating if the buffer is full or nearly full;
• a source of additional packets;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state, wherein the multiplexer controller is further responsive to the status signal from the input packet buffer to condition the multiplexer to delete a null packet from the input transport packet stream if the input packet buffer is full or nearly full.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate wherein:
• the first rate is greater than the second rate and the input transport packet stream contains null packets;
• a source of additional packets wherein the additional packet source further comprises:
• a source of auxiliary data packets, responsive to a source of auxiliary data, generating a status signal indicating that an auxiliary data packet is available;
• and
• a source of null packets;
• a null packet detector, coupled to the input transport packet stream source, for generating a status signal indicating if a next input transport packet is a null packet;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream wherein the multiplexer is further coupled to the auxiliary data packet source and the null packet source;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state wherein the multiplexer controller is responsive to the status signal from the auxiliary data packet source, for conditioning the multiplexer to insert an auxiliary data packet into the output packet stream as an additional packet if an auxiliary data packet is available, and otherwise to insert a null packet into the output packet stream as an additional packet and is further responsive to the status signal from the auxiliary packet source and the status signal from the null packet detector, for substituting an auxiliary data packet for the null packet in the output packet stream if an auxiliary data packet is available.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate;
• a source of additional packets;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream wherein the control signal source accumulates the amount of time the input transport packet stream is in advance of the output packet stream, and generates the control signal having the second state when the accumulated time is greater than a time duration of each output packet, and having the first state otherwise;
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state;
• and
• a modulator, coupled to the multiplexer, for modulating the output packet stream.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate wherein respective packets in the input packet stream are meant to be transmitted at corresponding predetermined times;
• a source of additional packets;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream wherein the control signal source accumulates the amount of time the input transport packet stream is in advance of the output packet stream, and generates the control signal having the second state when the accumulated time is greater than a time duration of each output packet, and having the first state otherwise;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state wherein the multiplexer controller conditions the multiplexer to insert respective input transport packets into the output packet stream at substantially the corresponding times.

In a remodulator system, a generator of an output packet stream having a first rate, comprising:

• a source of a stream of input transport packets having a second rate;
• a source of additional packets;
• a multiplexer, coupled to the input transport packet stream source and the additional packet source, for generating the output packet stream;
• a source of a control signal, responsive to the first and second rates, for generating the control signal having a first state when an input transport packet should be inserted into the output packet stream and a second state when additional packets should be inserted into the output packet stream wherein the control signal source accumulates the amount of time the input transport packet stream is in advance of the output packet stream, and generates the control signal having the second state when the accumulated time is greater than a time duration of each output packet, and having the first state otherwise;
• and
• a multiplexer controller, coupled between the control signal source and the multiplexer, for conditioning the multiplexer to insert an input transport packet into the output packet stream when the control signal has the first state, and to insert an additional packet into the output packet stream when the control signal has the second state;
• wherein:
• the input packet stream format is compatible with one of a QAM or QPSK modulation format;
• and
• the output packet stream format is compatible with an 8-VSB or 16-VSB modulation format.