Self-correlation detection in automatic gain calibration

A method of performing signal detection, the method comprising the steps of:

• obtaining a self-correlation measurement of a received signal;
• determining whether the self-correlation measurement exceeds a first threshold value;
• when the self-correlation measurement exceeds the first threshold value, determining how many times subsequently obtained self-correlation measurements of the received signal exceed a second threshold value during a given time period;
• when a count threshold is exceeded by the number of times the subsequently obtained self-correlation measurements exceed the second threshold value, determining that the received signal possibly includes a desired signal;
• estimating a power level of the received signal by summing instantaneous power calculations;
• estimating an in-band power level of identified in-band components of the received signal by summing instantaneous power calculations;
• comparing the power level of the received signal and the in-band power level;
• and
• when the received signal possibly includes the desired signal, determining that the received signal does include the desired signal if an increase in the in-band power level is at least proportionate to any increase in the power level of the received signal.

A method of performing signal detection, the method comprising the steps of:

• obtaining a self-correlation measurement of a received signal;
• determining whether the self-correlation measurement exceeds a first threshold value;
• when the self-correlation measurement exceeds the first threshold value, determining how many times subsequently obtained self-correlation measurements of the received signal exceed a second threshold value during a given time period;
• when a count threshold is exceeded by the number of times the subsequently obtained self-correlation measurements exceed the second threshold value, determining that the received signal possibly includes a desired signal;
• estimating an in-band power level of identified in-band components of the received signal by summing instantaneous power calculations;
• and
• when the received signal possibly includes the desired signal, determining that the received signal does include the desired signal if the in-band power level is at least a minimum size,
• wherein the step of estimating the in-band power level uses most of but less than all samples identified as being in-band components.

A method for detecting a desired signal, the method comprising the steps of:

• estimating a power level of the received signal by summing instantaneous power calculations;
• filtering the received signal to generate a filtered signal consisting substantially of components of the received signal that are at a desired data sampling rate and within a desired frequency range of the desired signal;
• estimating a power level of the filtered signal by summing instantaneous power calculations;
• using the power level of the received signal and the power level of the filtered signal to perform a strong signal detection procedure to detect a strong desired signal in the received signal;
• and
• using the power level of the received signal and the power level of the filtered signal to perform a weak signal detection procedure to detect a weak desired signal in the received signal.

A system for detecting a desired signal in an automatic gain control, comprising:

• a power detector for estimating a power of an input signal at a plurality of times by summing instantaneous power calculations, and thereby a power level of a received signal;
• a comparison circuit for comparing the power of the input signal at various times to determine the presence of the received signal;
• a filter to pass substantially only components of the received signal that are at a desired data sampling rate and within a desired frequency range of the desired signal, thereby obtaining a filtered signal;
• a power detector to estimate a power level of the filtered signal by summing instantaneous power calculations;
• and
• control logic, wherein the control logic uses the power levels of the received and filtered signals to perform a strong signal detection to detect a strong desired signal in the received signal and to perform a weak signal detection to detect a weak desired signal in the received signal.

A method of performing signal detection, the method comprising the steps of:

• obtaining self-correlation measurements of a received signal, wherein obtaining at least one of the self-correlation measurements comprises:
• taking multiple samples of the received signal;
• summing the product of each sample and the complex conjugate of one of a plurality of previously obtained samples taken a predetermined amount of time earlier;
• and
• normalizing the sum thus obtained;
• determining whether the received signal may be a desired signal by operating upon the self-correlation measurements using a plurality of threshold values;
• estimating an in-band power level of identified in-band components of the received signal by summing instantaneous power calculations of the multiple samples of the received signal;
• estimating a received signal power level of the received signal by summing instantaneous power calculations of the multiple samples of the received signal;
• comparing the received signal power level and the in-band power level;
• and
• when the received signal power level possibly includes the desired signal, determining that the received signal does include the desired signal if an increase in the in-band power level is at least proportionate to any increase in the received signal power level.

A method of performing signal detection, the method comprising the steps of:

• obtaining self-correlation measurements of a received signal;
• determining whether the received signal may be a desired signal by operating upon the self-correlation measurements using a plurality of threshold values;
• estimating a power level of the received signal by summing instantaneous power calculations;
• estimating an in-band power level of identified in-band components of the received signal by summing instantaneous power calculations;
• comparing the power level of the received signal and the in-band power level;
• and
• when the received signal possibly includes the desired signal, determining that the received signal does include the desired signal if an increase in the in-band power level is at least proportionate to any increase in the power level of the received signal.

A method of performing signal detection, the method comprising the steps of:

• obtaining self-correlation measurements of a received signal;
• determining whether the received signal may be a desired signal by operating upon the self-correlation measurements using a plurality of threshold values;
• estimating an in-band power level of identified in-band components of the received signal by summing instantaneous power calculations;
• and
• when the received signal possibly includes the desired signal, determining that the received signal does include the desired signal if the in-band power level is at least a minimum size,
• wherein the step of estimating the in-band power level uses most of but less than all samples identified as being in-band components.