초록 ▼

An apparatus, a carrier medium storing instructions to implement a method, and a method for controlling the gain of a radio receiver for receiving packets of information in a wireless network. The receiver is connected to an antenna subsystem and has receive signal path including a plurality of sect

An apparatus, a carrier medium storing instructions to implement a method, and a method for controlling the gain of a radio receiver for receiving packets of information in a wireless network. The receiver is connected to an antenna subsystem and has receive signal path including a plurality of sections including a first section coupled to the antenna subsystem and a next section. Each section has an adjustable gain and is able to provide a measure of the signal strength at its output. The method includes waiting for a start of packet indication, providing a measure of the signal strength at the output of the first section and the next section, and adjusting the gains of the first and the next sections using the provided measured signal strengths. In one embodiment, the receive signal path includes a filter, the provided measure for the first section is before the filter, and the provided measure for the second section is after the filter. The gain adjusting sets first section's gain according to the measured signal strength at the output of the first section and sets the next section's gain according to the provided measure of signal strength at the output of the next section relative to the provided measure of signal strength at the output of the first section. In one embodiment, the gain adjusting o is carried out in sequential AGC stages, one stage setting the gain of one or more sections.

대표청구항 ▼

We claim: 1. A radio receiver comprising: a receive signal path including: a filter; a pre-filter section prior to the filter, the pre-filter section including at least one adjustable gain element configured to provide an adjustable gain to the pre-filter section; at least two post-filter sections

We claim: 1. A radio receiver comprising: a receive signal path including: a filter; a pre-filter section prior to the filter, the pre-filter section including at least one adjustable gain element configured to provide an adjustable gain to the pre-filter section; at least two post-filter sections after the filter, including a first post filter section immediately after the filter, the post-filter sections each including at least one adjustable gain element configured to provide an adjustable gain to the post-filter section; a pre-filter signal strength detector coupled to the pre-filter section configured to measure the relative strength of the signal at a point in the receive signal path prior to filtering by the filter, the pre-filter signal strength detector having an output coupled to a first analog-to-digital converter and a first calibrator configured to provide a first multi-bit calibrated measure of the relative strength of the signal at the prior-to-filtering point; a first post-filter signal strength detector coupled to the first -post-filter section configured to provide a measure of the relative strength of the signal at a first post-filtering point in the receive signal path after filtering by the filter, the first post-filter signal strength detector having an output coupled to a second analog-to-digital converter and a second calibrator configured to provide a second multi-bit calibrated measure of the relative strength of the signal at the first post-filtering point; an automatic gain controller (AGC controller) coupled to the outputs of first and second calibrators of the pre-filter and first post-filter signal strength detectors and further coupled to the variable gain elements configured to set the gains of the respective sections according to the pre-filter and first post-filter multi-bit calibrated signal strength measures, the setting being configured to respectively set the pre-filter signal strength and the first post-filter signal strength to a desired pre-filter signal power and a desired first post-filter signal power, respectively, the gains setting providing an overall gain setting for the receive path, the AGC controller further configured to determine respective averages of the pre-filter and first post filter multi-bit calibrated signal strength measures, to compare the pre-filter and of the first post-filter averaged multi-bit calibrated signal strength measures to respective pre-filter and first post-filter desired signal powers, and to adjust the gains of the respective pre-filter and of the first post-filter sections to reduce the differences between the averaged signal strength measures and desired signal powers; and a main multi-bit analog to digital converter (ADC) configured to convert the output of the last analog section in the receiver signal path to a digital output signal, the multi-bit ADC having an operating range for its input, such that the gain settings of the pre-filter and first post filter variable gain elements adapt to achieve the desired pre-filter and post-filter signal powers according to the signal characteristics, and take into account the amount of filtering provided by the filter, and such that the gain settings of the pre-filter and first post filter variable gain elements does not require use of the digital output signal of the multi-bit ADC, and such that at least the first stage is configured to bring the input of the ADC to within the operating range of the ADC, such that the gain setting of at least the last post-filter stage uses the output of the multi-bit ADC. 2. A receiver as recited in claim 1, wherein the AGC controller is further configured to correct each of the pre-filter and first post-filter signal strength indications so that the averages are corrected averages. 3. A receiver as recited in claim 2, wherein the correction of the pre-filter and first post-filter signal strength indications is in order to bring the indications to a common scale so that the indications may be compared, and wherein the adjusting of the gains of at least one of the sections depends on both the pre-filter and first post-filter corrected and averaged signal strength indications. 4. A receiver as recited in claim 2, wherein the AGC controller operates in sequential stages, each stage configured to set the gains of one or more sections to achieve desired signal strength levels including the desired pre-filter signal strength level and a desired post-filter signal strength levels, the adjustment of each section being by a variable amount that depends on the calibrated measures of the relative strength. 5. A receiver as recited in claim 4, wherein a first stage is configured to set the gain of the pre-filter section according to the pre-filter signal strength indication and to set the gain of the first post filter section according to both the pre-filter signal strength indication and the first post-filter signal strength indication, and other stages are configured to finalize the gain setting of any other post-filter sections, according to additional signal strength indications from the relevant sections. 6. A receiver as recited in claim 1, wherein the receive signal path includes an RF section operating at RF and an intermediate frequency IF section after the RF section operating at an intermediate frequency, and wherein the filter is in the intermediate frequency section of the receive signal path. 7. A receiver as recited in claim 6, wherein the signal path includes a second filter section including a second filter between any variable gain element in the first post-filter section and any variable gain element in the second post-filter section, such that the gain setting takes into account the amount of filtering by the second filter in addition to the amount of filtering by the first filter. 8. A receiver as recited in claim 1, wherein the desired pre-filter signal power and a desired post-filter signal power are selected in order to maximize the signal-to-noise-and-distortion at the end of the respective sections. 9. A receiver as recited in claim 5, wherein the first post-filter signal strength detector is coupled to the first pre-filter section, and wherein at least the first stage is configured to set the gain of the pre-filter section and first post filter section to bring the input of the multi-bit ADC to within the range of the ADC. 10. A method for controlling the gain of a radio receiver, the receiver having a receive signal path including a filter; a pre-filter section prior to the filter, the pre-filter section including at least one adjustable gain element configured to provide an adjustable gain to the pre-filter section; and at least two post-filter sections after the filter, including a first post filter section immediately after the filter, the post-filter sections each including at least one adjustable gain element configured to provide an adjustable gain to the respective post-filter section; the method comprising: accepting a first multi-bit calibrated measure of the pre-filter relative signal strength at a point in the receive signal path prior to filtering by the filter; accepting a second multi-bit calibrated measure of the post-filter relative signal strength at a first post-filtering point in the receive signal path after the filtering by the filter; determining respective averages of the first multi-bit calibrated measure and the second multi-bit calibrated measure; comparing the respective averages of the first and second multi-bit calibrated signal strength measures to a desired pre-filter signal power and a desired post-filter signal power; setting the gains of the respective sections to reduce the differences between the average first and second multi-bit calibrated signal strength measure and the desired pre-filter and desired post filter signal powers, respectively, the gain setting providing an overall gain setting for the receive signal path; analog to digital converting the output of the last analog section in the receiver signal path to a digital output signal using a multi-bit analog-to-digital converter (ADC) that has an operating range for its input, such that the gain settings of the pre-filter and post filter variable gain elements adapt to achieve the desired pre-filter and post-filter signal powers according to the signal characteristics, and take into account for the amount of filtering provided by the filter, such that the gain setting of the pre-filter and first post filter variable gain elements are configured to set the output of the last analog section in the receiver signal path to be within the operating range of the multi-bit ADC, and does not require use of the digital output signal from the converting, and such that the gain adjusting of any section subsequent to the first post filter section is based on the digital output signal from the analog to digital converting. 11. A method as recited in claim 10, wherein the accepting of the measures includes calibrating the pre and first post-filter signal strength measures so that they may be compared. 12. A method for controlling the gain of a radio receiver for receiving packets of information, the receiver connected to an antenna subsystem, the receiver including a receive signal path including a plurality of sections including a first section coupled to the antenna subsystem, a next section, and a multi-bit analog-to-digital converter (ADC) coupled to the output of the last analog section in the receiver signal path to output a digital output signal, the multi-bit ADC having an operating range for its input, each section having an adjustable gain, each section able to provide a multi-bit calibrated measure of the signal strength at its output; the method comprising: waiting for a start of packet indication; providing multi-bit calibrated measures of the signal strengths at the outputs of the first and the next sections; and adjusting the gains of the first and the next sections using the provided measures of signal strength, the adjusting being to respectively set the signal strength at respective outputs of the sections to respective desired levels, in order to set the overall gain of the receive signal path and in one or more early stages to cause the output of the last analog section in the receiver signal path to be within the operating range of the multi-bit ADC, such that the gain adjusting of at least the first section does not require use of the digital output signal from the multi-bit ADC and brings the input of the multi-bit ADC to within the multi-bit ADC's operating range, and the gain adjusting of at least one subsequent section is based on the multi-bit digital output signal from the multi-bit ADC. 13. A method as recited in claim 12, further comprising setting the gains of the sections to a default level prior to waiting for a start of packet indication. 14. A method as recited in claim 12, wherein the receiver includes a filter in the receive signal path, the providing a measure of the signal strength at the output of the first section being at a point before the filter, and the providing a measure of the signal strength at the output of the next section being at a point after the filtering, the method further comprising: correcting the provided measures of signal strength at the outputs of the first section and next section to determine measures on a common scale such that the corrected measures may be compared, wherein the gain adjusting adjusts at least one of the first or next section's gain according to both the provided measure of signal strength at the output of the first section and at the output of the next section. 15. A method as recited in claim 12, wherein the desired levels are selected in order to maximize the signal-to-noise-and-distortion at the end of the respective stages. 16. An AGC controller configured to control the gain of a radio receiver for receiving packets of information, the receiver including: a receive signal path including a plurality of sections, each section having an adjustable gain, the plurality of sections including a first section coupled to an antenna subsystem and a next section; a multi-bit analog-to-digital converter (ADC) coupled to the output of the last analog section in the receiver signal path and configured to output a digital output signal, the multi-bit ADC having an operating range for its input; and a signal strength measurer coupled to each section configured to provide a multi-bit measure of the signal strength at the section's output; the AGC controller being configured to: wait for a start of packet indication; and accept multi-bit measures of the signal strengths from the signal strength measurers at the outputs of the first and next sections; and adjust the gains of the first and the next sections using the accepted measures of signal strengths, the adjusting being to respectively set the signal strength at respective outputs of the sections to respective desired levels, in order to set the overall gain of the receive signal path and in one or more early stages to cause the output of the last analog section in the receiver signal path to be within the operating range of the multi-bit ADC, the gain adjusting of at least the first section not using the digital output signal from the multi-bit ADC, and causing the output of the last analog section to be within the operating range of the multi-bit ADC, and wherein the gain adjusting of at least the last analog section is based on the digital output signal from the multi-bit ADC. 17. An AGC controller as recited in claim 16, wherein the receiver includes a filter in the receive signal path, the signal strength measurer of the first section provides a measure of the signal strength at a point before the filter, and the signal strength measurer of the next section provides a measure of the signal strength at a point after the filter, such that the gain adjusting sets the first section's gain according to the accepted measure of signal strength at the output of the first section and sets the next section's gain according to the accepted measure of signal strength at the output of the next section relative to the accepted measure of signal strength at the output of the first section. 18. An apparatus for controlling the gain of a radio receiver for receiving packets of information, the receiver including: a receive signal path including a plurality of sections, each section including means to control the section's gain; means for analog-to-digital converting coupled to the output of the last analog section in the receiver signal path to output a multi-bit digital output signal, the means for analog-to-digital converting having input and an operating range for the input; and means for measuring a multi-bit measure of the signal strength at the section's output; the apparatus comprising: means for waiting for a start of packet indication; and means for carrying out a plurality of sequential AGC stages, each stage corresponding to adjusting the gain of one or more sections, the means for carrying out a sequential AGC stage including for each stage and corresponding sections: means for receiving multi-bit measures of the signal strengths at the end of the corresponding sections; means for comparing the measured signal strengths at the ends of the corresponding sections to respective desired signal strength levels for the respective corresponding sections, the means for comparing the measure at the end of the first section including means for averaging, such that the comparing for the first section is of an average of the measured signal strength at the end of the first section to a first section desired signal strength level; and means for adjusting the gains of the corresponding sections by a variable amount that depends on the differences between the respective desired levels and the respective measured signal strengths for the corresponding sections, such that during the first stage of the plurality of sequential AGC stages, the means for adjusting the gains is configured to adjust the gain of at least the first section without requiring use of the digital output signal to bring the input of the means for analog-to-digital converting to within the operating range of the means for analog-to-digital converting, wherein the means for adjusting the gain of at least the last analog section adjusts the gain based on the output of the means for analog-to-digital converting. 19. An apparatus as recited in claim 18, wherein the receiver includes a filter in the receive signal path, the means for measuring at the end of the first section being at a point before the filter, and the means for measuring at the end of the second section being at a point after the- filter. 20. A computer readable hardware storage medium configured with one or more computer readable instructions that when executed by one or more processors of a processing system carry out a method for controlling the gain of a radio receiver for receiving packets of information, the receiver including a receive signal path including a plurality of sections and a multi-bit analog-to-digital converter (ADC) coupled to the output of the last analog section in the receiver signal path to output a digital output signal, each section having an adjustable gain, each section providing a measure of the signal strength at its output; the method comprising: waiting for a start of packet indication; and carrying out a plurality of AGC stages, each stage corresponding to one or more sections, including for each stage and corresponding sections: measuring the signal strengths at the ends of the corresponding sections to provide multi-bit calibrated signal strengths; comparing the measured signal strengths at the ends of the corresponding sections to a respective desired signal strength levels for the corresponding sections; and adjusting the gains of the corresponding sections according to the differences between the respective desired levels and the respective measured signal strengths for the corresponding sections, the adjusting being to respectively set the signal strength at respective outputs of the sections to respective desired levels, in order to set the overall gain of the receive signal path and in one or more early stages to cause the output of the last analog section in the receiver signal path to be within the operating range of the multi-bit ADC, such that the gain adjusting of at least the first section does not require use of the digital output signal from the multi-bit ADC and causes the output of the last analog section to be within the operating range of the multi-bit ADC, and such that the gain adjusting of at least the last analog section is based on the digital output from the multi-bit ADC. 21. A computer readable hardware storage medium as recited in claim 20, wherein the receiver includes a filter in the receive signal path, the measuring at the first stage being at a point before the filter, and the measuring at the second AGC stage being at a point after the filtering.