Category: Software
Hello,
We are working on the configuration of the X-band radar platform. Since we don't have a RF signal generator and a spectrum analyzer, we can only test the radar system by setting part of subarray on Stingray as Tx mode and the others as Rx mode. So we combine the example code "XBDP_SimpleRx.m" and "XBDP_SimpleTx.m". Then, the result of code is as following:
It appears that the results are incorrect, as the frequency of the transmitter (Tx) does not affect the results of the receiver (Rx). So we are wondering what's wrong with the configuration. We use the on-board LO signal on the ADXUD1A board. And we are not sure whether ADXUD1A is working well. The following is our control code, could you give us some suggestion?
In summary, we would like to know:
1. whether the code is correct.
2.how to see whether ADXUD1A is working well?
3. Do we need to enable the on-board LO on the software side?
Finally, we would really appreciate it if you could give us some advice! Looking forward to your reply!
clear all, close all, clc
%% Array Mapping
%verify element maps correctly to hardware!
subarray = ...
[[1 2 5 6 9 10 13 14];... %subarray 1
[3 4 7 8 11 12 15 16];... %subarray 2
[19 20 23 24 27 28 31 32];... %subarray 3
[17 18 21 22 25 26 29 30]]'; %subarray 4
subarray_ref = [2 4 18 20]; %subarray reference elements
dac_map = [4 3 2 1]; %DAC map to subarray
dac_ref = 4; %DAC reference channel
adc_map = [4 2 1 3]; %ADC map to subarray
adc_ref = 4; %ADC reference channel
%% Config Dev Kit
% uri = 'ip:192.168.1.101';
uri = 'ip:169.254.183.161';
amplitude = 2^15*db2mag(-6); %Tx Baseband Amplitude [dBFS]
interFreq = 4.5e9; %Tx NCO Frequency [Hz]
fs_TxIQ = 250e6; %Tx Decimated IQ Sample Rate [Hz]
periods = 32; %Desired Number Of Periods For Tx Signal
basebandFreq = fs_TxIQ/periods; %Baseband Frequency [Hz]
%Setup AD9081 Tx
tx = adi.AD9081.Tx;
tx.uri = uri;
tx.EnabledChannels = [1 2 3 4];%Enabled Tx Channels, Only Needed for DMA
tx.SamplesPerFrame = 2^10; %Number Of Samples
tx.NCOEnables = ones(1,numel(tx.EnabledChannels));
tx.ChannelNCOGainScales = ones(1,numel(tx.EnabledChannels)).*0.5; %MxFE0 Digital Gain Code
%DMA Configuration
tx.DataSource = 'DMA'; %'DMA' or 'DDS'
tx.EnableCyclicBuffers = 1; %0: Don't Cycle Tx Waveform, 1: Cycle Tx Waveform
swv1 = dsp.SineWave(amplitude, basebandFreq);
swv1.ComplexOutput = true;
swv1.SamplesPerFrame = tx.SamplesPerFrame;
swv1.SampleRate = fs_TxIQ;
y = swv1();
waveform = ones(tx.SamplesPerFrame,numel(tx.EnabledChannels)).*y;
release(tx)
tx(waveform);
tx.MainNCOFrequencies = ones(1,numel(tx.EnabledChannels))*interFreq; %NCO Frequency
tx.MainNCOPhases = zeros(1,numel(tx.EnabledChannels)); %NCO Phase
% Setup ADAR1000EVAL1Z in Tx Mode
sray = adi.Stingray;
sray.uri = uri;
sray.Mode(2,:) = {'Tx'}; %set mode, 'Rx', 'Tx, 'Disabled'
txPhaseCalOffsets = zeros(size(sray.TxGain));
sray.TxAttn(3:4,:) = 1; %1: Attenuation Off, 0: Attenuation On
sray.TxGain(3:4,:) = 127; %127: Highest Gain, 0: Lowest Gain, Decimal Value
sray(); %Stingray Constructor
sray.SteerTx(0,0,txPhaseCalOffsets); %Broadside
sray.LatchTxSettings; %Latch settings to devices
%Setup ADXUD1AEBZ, %Tx Mode
sray.TXRX0 = 0; %0: RX, 1: TX
sray.TXRX1 = 0;
sray.TXRX2 = 1;
sray.TXRX3 = 1;
% sray.RxGainMode = 0; %0: Low Gain, 1: High Gain, RX Mode only
sray.ADF4371Frequency = 14.5e9; %program if using on-board LO PLL
sray.PllOutputSel = 1; %1: ADF4371 RF1 (8 GHz to 16 GHz), 0: ADF4371 RF2 (16 GHz to 32 GHz)
sray.PABiasOn(3:4,:) = -1.06;
sray.TxPAEnable(3:4,:) = true;
sray.TxPowerDown(3:4,:) = false; %Enable all channels for TX
detect = sray.LTC2314RFPower; %reads detected power (dBm) for J9 Input
sray.TxPowerDown(3:4,:) = true; %Disable all channels for TX
%% Rx
fs_RxTxIQ = 250e6; %I/Q Data Rate in MSPS
%Setup AD9081 RX
rx = adi.AD9081.Rx;
rx.uri = uri;
rx.EnabledChannels = [1 2 3 4];
rx.MainNCOFrequencies = ones(1,4)*0e6; %NCO Frequency
rx.SamplesPerFrame = 2^12; %Number Of Samples To Capture: 4096
rx.kernelBuffersCount = 1; %Number Of Buffers To Subsequently Capture
rx.EnablePFIRs = true; %MxFE pFIR Configuration; false: Don't Use pFIRs, true: Use pFIRs
rx.PFIRFilenames = 'disabled.cfg'; %MxFE0 pFIR File
data = rx(); %Initialize The Rx System; Grab The Rx Data Into 'data' Matrix
rx.setRegister(hex2dec('FF'),'19'); %Fine DDC Page
rx.setRegister(hex2dec('61'),'283'); %Fine DDC Control, bypass fine NCO
% Setup ADAR1000EVAL1Z in RX Mode
rxPhaseCalOffsets = zeros(size(sray.RxGain));
sray.Mode(1,:) = {'Rx'}; %set mode, 'Rx', 'Tx, 'Disabled'
sray.RxAttn(1:2,:) = 1; %1: Attenuation Off, 0: Attenuation On
sray.RxGain(1:2,:) = 127; %127: Highest Gain, 0: Lowest Gain, Decimal Value
sray(); %constructor to write properties to hardware
sray.SteerRx(0,0,rxPhaseCalOffsets); %Broadside
sray.LatchRxSettings; %Latch SPI settings to devices
%Setup ADXUD1AEBZ, %Rx High Gain Mode
sray.RxGainMode = 1; %0: Low Gain, 1: High Gain - RX Mode only
% sray.ADF4371Frequency = 14.5e9; %program if using on-board LO PLL
% sray.PllOutputSel = 1; %1: ADF4371 RF1 (8 GHz to 16 GHz), 0: ADF4371 RF2 (16 GHz to 32 GHz)
sray.RxPowerDown(1:2,:) = false; %Enable RX Channels
data = rx(); %capture data from ADCs, 4096x4 matrix
sray.RxPowerDown(1:2,:) = true; %Disable Rx channels
combinedComplexData = sum(data,2); %complex addition for all 4 ADCs
%% plot
%Calculate FFT of sample domain data for frequency response plots
hanningWindow = hanning(rx.SamplesPerFrame);
hanNoiseEqBw = enbw(hanningWindow);
scalingFactor = sqrt(hanNoiseEqBw)*(rx.SamplesPerFrame/2)*2^15;
scalingFactorArray = sqrt(hanNoiseEqBw)*(rx.SamplesPerFrame/2)*2^17; %bit growth due to coherent combining 4 ADCs
%FFT for each subarray
complexData = data./scalingFactor;
windowedData = complexData.*hanningWindow;
fftComplex = fft(windowedData);
fftComplexShifted = fftshift(fftComplex);
fftMags = abs(fftComplexShifted);
fftMagsdB = 20*log10(fftMags);
freqAxis = linspace((-fs_RxTxIQ/1e6/2), (fs_RxTxIQ/1e6/2), length(fftMagsdB));
%frequency response plot for each subarray
figure
subplot(2,2,1)
plot(freqAxis, fftMagsdB(:,adc_map(1)))
grid on;
hold on;
title('Frequency Response Of Subarray 1');
xlabel('Frequency (MHz)','FontSize',12);
ylabel('Amplitude (dBFS)','FontSize',12);
axis([-fs_RxTxIQ/1e6/2, fs_RxTxIQ/1e6/2, -120, 0]);
subplot(2,2,2)
plot(freqAxis, fftMagsdB(:,adc_map(2)))
grid on;
hold on;
title('Frequency Response Of Subarray 2');
xlabel('Frequency (MHz)','FontSize',12);
ylabel('Amplitude (dBFS)','FontSize',12);
axis([-fs_RxTxIQ/1e6/2, fs_RxTxIQ/1e6/2, -120, 0]);
subplot(2,2,3)
plot(freqAxis, fftMagsdB(:,adc_map(3)))
grid on;
hold on;
title('Frequency Response Of Subarray 3');
xlabel('Frequency (MHz)','FontSize',12);
ylabel('Amplitude (dBFS)','FontSize',12);
axis([-fs_RxTxIQ/1e6/2, fs_RxTxIQ/1e6/2, -120, 0]);
subplot(2,2,4)
plot(freqAxis, fftMagsdB(:,adc_map(4)))
grid on;
hold on;
title('Frequency Response Of Subarray 4');
xlabel('Frequency (MHz)','FontSize',12);
ylabel('Amplitude (dBFS)','FontSize',12);
axis([-fs_RxTxIQ/1e6/2, fs_RxTxIQ/1e6/2, -120, 0]);Best,
Dongyu
