SymbolSynchronizer Class Reference

#include <symsync.h>

Public Member Functions
	SymbolSynchronizer ()
	~SymbolSynchronizer ()
Real	run (const Sample &s)
liquid_float_complex	runZ (const Sample &s)

Private Attributes
symsync_crcf	m_sync
liquid_float_complex	m_z [4+4]
liquid_float_complex	m_z0
int	m_syncSampleCount

Detailed Description

Definition at line 25 of file symsync.h.

Constructor & Destructor Documentation

SymbolSynchronizer()

SymbolSynchronizer::SymbolSynchronizer

(

)

Definition at line 23 of file symsync.cpp.

References m_sync, and m_syncSampleCount.

{
    // For now use hardcoded values:
    //   - RRC filter
    //   - 4 samples per symbol
    //   - 5 symbols delay filter
    //   - 0.5 filter excess bandwidth factor
    //   - 32 filter elements for the internal polyphase filter
    m_sync = symsync_crcf_create_rnyquist(LIQUID_FIRFILT_RRC, 4, 5, 0.5f, 32);
    //   - 0.02 loop filter bandwidth factor
    symsync_crcf_set_lf_bw(m_sync, 0.01f);
    //   - 4 samples per symbol output rate
    symsync_crcf_set_output_rate(m_sync, 4);
    m_syncSampleCount = 0;
}

~SymbolSynchronizer()

SymbolSynchronizer::~SymbolSynchronizer

(

)

Definition at line 39 of file symsync.cpp.

References m_sync.

{
    symsync_crcf_destroy(m_sync);
}

Member Function Documentation

run()

Real SymbolSynchronizer::run

(

const Sample &

s

)

Definition at line 44 of file symsync.cpp.

References i, Sample::m_imag, Sample::m_real, m_sync, m_syncSampleCount, m_z, and SDR_RX_SCALEF.

{
    unsigned int nn;
    Real v = -1.0f;
    liquid_float_complex y = (s.m_real / SDR_RX_SCALEF) + (s.m_imag / SDR_RX_SCALEF)*I;
    symsync_crcf_execute(m_sync, &y, 1, m_z, &nn);

    for (unsigned int i = 0; i < nn; i++)
    {
        if (nn != 1) {
            qDebug("SymbolSynchronizer::run: %u", nn);
        }

        if (m_syncSampleCount % 4 == 0) {
            v = 1.0f;
        }

        if (m_syncSampleCount < 4095) {
            m_syncSampleCount++;
        } else {
            qDebug("SymbolSynchronizer::run: tau: %f", symsync_crcf_get_tau(m_sync));
            m_syncSampleCount = 0;
        }
    }

    return v;
}

runZ()

liquid_float_complex SymbolSynchronizer::runZ

(

const Sample &

s

)

Definition at line 72 of file symsync.cpp.

References i, Sample::m_imag, Sample::m_real, m_sync, m_syncSampleCount, m_z, m_z0, and SDR_RX_SCALEF.

{
    unsigned int nn;
    liquid_float_complex y = (s.m_real / SDR_RX_SCALEF) + (s.m_imag / SDR_RX_SCALEF)*I;
    symsync_crcf_execute(m_sync, &y, 1, m_z, &nn);

    for (unsigned int i = 0; i < nn; i++)
    {
        if (nn != 1) {
            qDebug("SymbolSynchronizer::run: %u", nn);
        }

        if (m_syncSampleCount == 0) {
            m_z0 = m_z[i];
        }

        if (m_syncSampleCount < 3) {
            m_syncSampleCount++;
        } else {
            m_syncSampleCount = 0;
        }
    }

    return m_z0;
}

Member Data Documentation

m_sync

symsync_crcf SymbolSynchronizer::m_sync

private

Definition at line 35 of file symsync.h.

Referenced by run(), runZ(), SymbolSynchronizer(), and ~SymbolSynchronizer().

m_syncSampleCount

int SymbolSynchronizer::m_syncSampleCount

private

Definition at line 38 of file symsync.h.

Referenced by run(), runZ(), and SymbolSynchronizer().

m_z

liquid_float_complex SymbolSynchronizer::m_z[4+4]

private

Definition at line 36 of file symsync.h.

Referenced by run(), and runZ().

m_z0

liquid_float_complex SymbolSynchronizer::m_z0

private

Definition at line 37 of file symsync.h.

Referenced by runZ().

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The documentation for this class was generated from the following files:

• sdrbase/dsp/symsync.h
• sdrbase/dsp/symsync.cpp