METHOD AND PEAK REDUCTION UNIT FOR LIMITING A PEAK OR GROUP OF PEAKS OF AN AGGREGATED BASEBAND CARRIER SIGNAL IN A RADIO TRANSMITTER
First Claim
1. Method for limiting a peak or group of peaks of an aggregated baseband carrier signal to a threshold value, said aggregated baseband carrier signal comprising digital carrier signals allocated to passbands which are separated by intermediate free frequency bands, said passbands and intermediate free frequency bands being distributed according to an aggregated carrier passband configuration in the frequency baseband, wherein one or more samples of the aggregated baseband carrier signal form a peak or group of peaks, which samples are complex having absolute values exceeding a threshold value, a peak value comprising an peak absolute value, being the difference between the absolute value of the corresponding sample and the threshold value, and the phase of the corresponding sample, said method comprising the steps of:
- Delaying an aggregated baseband carrier signal;
Identifying samples constituting a peak or a group of peaks by determining the peak absolute values and a maximum absolute peak value of said peak or group of peaks within a predetermined search length from each identified peak;
Determining the phase value and a synchronization time for the sample corresponding to the peak maximum absolute value;
Retrieving a stored, predetermined filter impulse response determined according to the aggregated carrier passband configuration and comprising samples constituting a peak or a group of peaks, wherein one peak sample is a maximum peak sample;
Adjusting the samples of the predetermined filter impulse response using the phase value and the peak maximum absolute value of the maximum peak sample; and
Combining the delayed aggregated baseband carrier signal and the adjusted predetermined filter impulse response by synchronizing their maximum peak samples using the synchronization time and their opposite phase values resulting in an output aggregated baseband signal wherein each sample is limited within the threshold value.
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Abstract
This disclosure relates to a peak reduction circuit and method for reducing peaks by identifying peak sample values exceeding a pre-set threshold value in an aggregated baseband carrier signal and determining a maximum peak sample by detecting its maximum peak absolute value and phase. A search is performed a pre-determined search length beyond an identified peak. A stored, predetermined filter impulse response based on the carrier passband configuration is retrieved and its amplitude and phase of the predetermined filter impulse response is adjusted by means of the phase and absolute value of the determined maximum peak sample. Finally, the aggregated baseband carrier signal and the adjusted predetermined filter impulse response are combined by synchronizing their maximum peaks and their opposite phase values for adjusting the aggregated baseband carrier signal to said pre-set threshold value.
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Citations
11 Claims
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1. Method for limiting a peak or group of peaks of an aggregated baseband carrier signal to a threshold value, said aggregated baseband carrier signal comprising digital carrier signals allocated to passbands which are separated by intermediate free frequency bands, said passbands and intermediate free frequency bands being distributed according to an aggregated carrier passband configuration in the frequency baseband, wherein one or more samples of the aggregated baseband carrier signal form a peak or group of peaks, which samples are complex having absolute values exceeding a threshold value, a peak value comprising an peak absolute value, being the difference between the absolute value of the corresponding sample and the threshold value, and the phase of the corresponding sample, said method comprising the steps of:
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Delaying an aggregated baseband carrier signal; Identifying samples constituting a peak or a group of peaks by determining the peak absolute values and a maximum absolute peak value of said peak or group of peaks within a predetermined search length from each identified peak; Determining the phase value and a synchronization time for the sample corresponding to the peak maximum absolute value; Retrieving a stored, predetermined filter impulse response determined according to the aggregated carrier passband configuration and comprising samples constituting a peak or a group of peaks, wherein one peak sample is a maximum peak sample; Adjusting the samples of the predetermined filter impulse response using the phase value and the peak maximum absolute value of the maximum peak sample; and Combining the delayed aggregated baseband carrier signal and the adjusted predetermined filter impulse response by synchronizing their maximum peak samples using the synchronization time and their opposite phase values resulting in an output aggregated baseband signal wherein each sample is limited within the threshold value. - View Dependent Claims (2, 3, 4, 5)
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6. Peak reduction circuit for limiting peak or group of peaks of an aggregated baseband carrier signal to a threshold value, said aggregated baseband carrier signal comprising digital carrier signals allocated to passbands which are separated by intermediate free frequency bands, said passbands and intermediate free frequency bands being distributed according to an aggregated carrier passband configuration in the frequency baseband, wherein one or more samples of the aggregated baseband carrier signal form a peak or group of peaks, which samples are complex having absolute values exceeding a threshold value, a peak value comprising a peak absolute value, being the difference between the absolute value of the corresponding sample and the threshold value, and the phase of the corresponding sample, the peak reduction circuit comprising:
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a delay buffer for receiving and delaying an aggregated baseband carrier signal, a controller for controlling a peak extractor circuit, and a peak determination circuit, wherein the peak extractor circuit, is adapted to identify samples constituting a peak or a group of peaks by determining the peak absolute values, the peak determination circuit is adapted to determine a peak maximum absolute value of said peak or group of peaks within a predetermined search length from each identified peak and to determine the phase value for the sample corresponding to the peak maximum absolute value; said controller comprising a processor adapted to determine a synchronization time for the sample corresponding to the peak maximum absolute value and to retrieve from a storage a stored, predetermined filter impulse response determined according to the aggregated carrier passband configuration and comprising samples constituting a peak or a group of peaks, wherein one peak sample is a maximum peak sample; a multiplication circuit configured to adjust the samples of the predetermined filter impulse response using the phase value and the maximum peak absolute value of the maximum peak sample; a combining circuit adapted to combine the delayed aggregated baseband carrier signal and the adjusted predetermined filter impulse response, wherein the controller is adapted to synchronize by using the synchronization time their maximum peaks and their opposite phase values resulting in an output aggregated baseband signal wherein each sample is limited within the threshold value. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification