evdoForwardWaveformGenerator

Create a structure to transmit a Revision A 1xEV-DO channel consisting of three 1024-bit packets transmitted over 2 slots with a 64-bit preamble length.

config = evdoForwardReferenceChannels('RevA-1024-2-64',3);

Verify that the function created a 1-by-3 structure array. Each element in the structure array corresponds to a data packet.

config.PacketSequence

ans=1×3 struct array with fields:
    MACIndex
    PacketSize
    NumSlots
    PreambleLength

Examine the first structure element to verify the packet size, number of slots, and preamble length match what you specified in the function call.

config.PacketSequence(1)

ans = struct with fields:
          MACIndex: 0
        PacketSize: 1024
          NumSlots: 2
    PreambleLength: 64

Generate the waveform.

wv = evdoForwardWaveformGenerator(config);

Create a structure to generate two packets of a 1.8 Mbps Release 0 channel.

config = evdoForwardReferenceChannels("Rel0-1843200-1",2);

Calculate the sample rate of the waveform.

fs = 1.2288e6 * config.OversamplingRatio;

Disable the internal filter of the evdoForwardWaveformGenerator function. Generate the 1xEV-DO waveform.

config.FilterType = "off";
wv = evdoForwardWaveformGenerator(config);

sa = spectrumAnalyzer( ...
    SampleRate=fs, ...
    ChannelNames=["1xEv-DO","1xEV-DO filtered"]);

Create a lowpass FIR filter with a 500 kHz passband, a 750 kHz stopband, and a stopband attenuation of 60 dB.

d = designfilt("lowpassfir", ...
    PassbandFrequency=500e3, ...
    StopbandFrequency=750e3, ...
    StopbandAttenuation=60, ...
    SampleRate=fs);

Change the filter type to "Custom" and specify the coefficients from the digital filter, d.

config.FilterType = "Custom";
config.CustomFilterCoefficients = d.Numerator;

Generate the waveform using the custom filter coefficients.

wvfiltered = evdoForwardWaveformGenerator(config);

Plot the spectrum of the unfiltered and filtered 1xEV-DO waveform. The filter attenuates the waveform by 60 dB for frequencies outside of $$\pm$$ 750 kHz.

sa(wv,wvfiltered)