Automatic power control in a data transmission system

A system for use in transmitting digital data, the system comprising:

• (a) a modulation element configured to receive blocks of digital data and to modulate each block using one of at least two digital modulation types, each having different associated power levels;
• (b) an automatic power control element configured to:
• (1) apply a selected gain value to each of the blocks of modulated data before transmission;
• (2) select the gain value to be applied to each of the blocks of modulated data from a group of at least two predetermined gain values, each corresponding to one of the digital modulation types, where the selected gain values maintain substantially constant average transmission power level among all of the blocks of modulated data;
• and
• a modulation controller configured to provide a signal to the modulation element and to the automatic power control element indicating which of the digital modulation types is to be used in transmitting each block of modulated data.

A system for use in transmitting digital data, the system comprising:

• (a) a modulation element configured to receive blocks of digital data and to modulate each block using one of at least two digital modulation types;
• (b) an automatic power control element configured to:
• (1) apply a selected gain value to each of the modulated blocks of data before transmission;
• (2) select the gain value to be applied to each of the blocks of modulated data from a group of at least two predetermined gain values, each corresponding to one of the digital modulation types;
• and
• wherein the digital modulation types have different associated average power levels, and the automatic power control element is configured to select the gain values to maintain substantially constant average transmission power level among all of the blocks of modulated data.

An automatic power control system for use in transmitting digital data, the system comprising:

• (a) a gain element configured to:
• (1) receive blocks of digital data, each of which is to be transmitted using one of at least two different digital modulation types, each having different associated power levels;
• and
• (2) apply a selected gain value to each of the blocks of modulated data before transmission;
• and
• (b) a control element configured to select the gain value to be applied to each of the blocks of modulated data from a group of at least two predetermined gain values, each corresponding to one of the digital modulation types, where the selected gain values maintain substantially constant average transmission power level among all of the blocks of modulated data;
• and
• (c) at least one data storage device that stores each of the predetermined gain values in a dedicated storage location.

An automatic power control system for use in transmitting digital data, the system comprising:

• (a) a gain element configured to:
• (1) receive blocks of digital data, each of which is to be transmitted using one of at least two different digital modulation types;
• and
• (2) apply a selected gain value to each of the blocks of modulated data before transmission;
• and
• (b) a control element configured to select the gain value to be applied to each of the blocks of modulated data from a group of at least two predetermined gain values, each corresponding to one of the digital modulation types;
• and
• wherein the digital modulation types have different associated average power levels, and the control element is configured to select the gain values to maintain substantially constant average transmission power level among all of the blocks of modulated data.

A method for use in transmitting digital data comprising:

• storing a group of at least two predetermined gain values;
• receiving blocks of digital data;
• modulating each block using one of at least two digital modulation types;
• selecting a gain value to be applied to each of the blocks of modulated data from the group of at least two predetermined gain values, each corresponding to one of the digital modulation types, each digital modulation type having a different associated power level;
• and
• applying the selected gain value to each of the blocks of modulated data before transmission, where the selected gain values maintain substantially constant average transmission power level among all of the blocks of modulated data.

A method for use in transmitting digital data comprising:

• receiving blocks of digital data;
• modulating each block using one of at least two digital modulation types;
• selecting a gain value to be applied to each of the blocks of modulated data from a group of at least two predetermined gain values, each corresponding to one of the digital modulation types;
• applying the selected gain value to each of the blocks of modulated data before transmission;
• and
• wherein the digital modulation types have different associated average power levels and selecting a gain value includes selecting the values to maintain substantially constant average transmission power level among all of the blocks of modulated data.

A system for use in transmitting digital data, the system comprising:

• a data blocking element configured to receive a stream of digital data and to divide the stream into blocks of digital data;
• a modulation element configured to receive the blocks of digital data and to modulate each block using one of at least two digital modulation types, including QPSK and k-QAM, where k is a power of two, where the digital modulation types have different associated average power levels;
• an automatic power control element including:
• a gain element that applies a selected gain value to each of the blocks of modulated data before transmission;
• and
• a control element that selects the gain value to be applied to each of the blocks of modulated data from a group of at least two predetermined gain values, each corresponding to one of the digital modulation types, the control element including a switch that selectively provides the gain values to the gain element in response to a signal indicating the digital modulation type to be used in transmitting each of the blocks of data, such that the selected gain values maintain substantially constant average transmission power level among all of the blocks of modulated data;
• and
• a transmission element configured to transmit each block of modulated data over a cable TV network during a predetermined time slot assigned to the block of modulated data.