Preliminary Technical
Data
Rev. PrA | Page 45 of 82
Interpolator
The interpolator can be programmed to interpolate the data by 4, 2, or 1. The main purpose of the interpolator is to produce finer
timing resolution so that the peak detector can find the location of the peaks more accurately. The interpolator takes in the
transmitter data and outputs the interpolated data to the peak detec tor.
Peak Detector
The purpose of the peak detector block is to find groups of peaks that are above a certain threshold and then output the peak I
and Q values along with peak locations relative to the first peak. The peak detector looks for peaks that are above a certain
programmable threshold. Since peaks don’t occur very often, a coarse peak detection on every sample is performed using the
following method:
1.
(Coarse peak detection)
If this condition is false, then there is no need to compute the complex calculation. This saves some power by
avoiding frequent multiplications. In the case when the sample is larger, the magnitude of the incoming complex signal
is checked to determine if it is above the threshold, using the inequality shown in Step 2 below.
2.
(Fine peak detection)
If the condition above is true, multiple consecutive samples that exceed the threshold can be found. These peaks can be
corrected using a single pulse which is superimposed on to the maximum valued peak of the group of samples.
The peak detector sends this peak’s location along with the values of the peak samples into the linear system solver.
Linear System Solver
After getting the peak location and its corresponding values, the linear solver calculates the complex difference between the peak
value and the threshold. The linear solver calculates the weights for various pulses required to cancel the peak.
These weights and peak location values are then used to scale and time-shift the spectrally shaped pulses and generate the
correction pulse. This correction pulse is then subtracted from the transmitter input data to generate the output signal (with a
low PAR).
Pulse RAM
The pulse RAM holds the correction pulse for the carrier. It is possible to load two correction pulses corresponding to two
desired carrier configurations. The user can pre-load these two correction pulses and be able to switch between two carrier
configurations on-the-fly. This mode is known as the hot-swap mode and is addressed by the
adi_adrv9010_CfrCorrectionPulseWrite_v2 API command.
API SOFTWARE INTEGRATION
The API functions described in this section are required to set up the CFR block in the transceiver. This section first outlines the
procedures to use CFR functionality and provides steps where each API function is called. Then it goes over the various data
structures used to set up the CFR engine, as well as list out the different API functions used to configure the CFR block in the
following sections.
Procedure for setting up CFR
CFR can be set any time after part initialization. After setting up CFR parameters and loading correction pulses, the init cal enum
ADI_ADRV9025_CFR should be used to run CFR initial calibration. The recommended sequence to configure the CFR engine is:
1. Program the CFR control configuration via adi_adrv9025_CfrControlConfigSet
2. Verify the CFR control cofiguration via adi_adrv9025_CfrCtrlConfigGet
3. Program the CFR correction pulse using adi_adrv9025_CfrCorrectionPulseWrite_v2
4. Enable the CFR engine via adi_adrv9025_CfrEnableSet
5. Optionally configure the hard clipper via adi_adrv9025_CfrHardClipperConfigSet
6. Execute the CFR init cal via adi_adrv9025_InitCalsRun
7. Optionally set the active correction pulse to use in Mode 1 via adi_adrv9025_CfrActiveCorrectionPulseSet API for carrier
config hot-swapping
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