C++ (Cpp) agc_crcf_get_gain示例

示例#1

文件： agc_crcf_autotest.c 项目： Clivia/liquid-dsp

// 
// Test AC gain control
//
void autotest_agc_crcf_ac_gain_control()
{
    // set paramaters
    float gamma = 0.1f;             // nominal signal level
    float bt    = 0.1f;             // bandwidth-time product
    float tol   = 0.001f;           // error tolerance
    float dphi  = 0.1f;             // NCO frequency

    // create AGC object and initialize
    agc_crcf q = agc_crcf_create();
    agc_crcf_set_bandwidth(q, bt);

    unsigned int i;
    float complex x;
    float complex y;
    for (i=0; i<256; i++) {
        x = gamma * cexpf(_Complex_I*i*dphi);
        agc_crcf_execute(q, x, &y);
    }

    if (liquid_autotest_verbose)
        printf("gamma : %12.8f, rssi : %12.8f\n", gamma, agc_crcf_get_signal_level(q));

    // Check results
    CONTEND_DELTA( agc_crcf_get_gain(q), 1.0f/gamma, tol);

    // destroy AGC object
    agc_crcf_destroy(q);
}

示例#2

文件： agc_crcf_autotest.c 项目： Clivia/liquid-dsp

// 
// Test DC gain control
//
void autotest_agc_crcf_dc_gain_control()
{
    // set paramaters
    float gamma = 0.1f;     // nominal signal level
    float bt    = 0.1f;     // bandwidth-time product
    float tol   = 0.001f;   // error tolerance

    // create AGC object and initialize
    agc_crcf q = agc_crcf_create();
    agc_crcf_set_bandwidth(q, bt);

    unsigned int i;
    float complex x = gamma;    // input sample
    float complex y;            // output sample
    for (i=0; i<256; i++)
        agc_crcf_execute(q, x, &y);
    
    // Check results
    CONTEND_DELTA( crealf(y), 1.0f, tol );
    CONTEND_DELTA( cimagf(y), 0.0f, tol );
    CONTEND_DELTA( agc_crcf_get_gain(q), 1.0f/gamma, tol );

    // destroy AGC object
    agc_crcf_destroy(q);
}

示例#3

文件： ofdmoqamframe64sync.c 项目： shishougang/liquid-dsp

void ofdmoqamframe64sync_execute_plcpshort(ofdmoqamframe64sync _q, float complex _x)
{
    // run AGC, clip output
    float complex y;
    agc_crcf_execute(_q->sigdet, _x, &y);
    //if (agc_crcf_get_signal_level(_q->sigdet) < -15.0f)
    //    return;
    if (cabsf(y) > 2.0f)
        y = 2.0f*liquid_cexpjf(cargf(y));

    // auto-correlators
    //autocorr_cccf_push(_q->autocorr, _x);
    autocorr_cccf_push(_q->autocorr, y);
    autocorr_cccf_execute(_q->autocorr, &_q->rxx);

#if DEBUG_OFDMOQAMFRAME64SYNC
    windowcf_push(_q->debug_rxx, _q->rxx);

    windowf_push(_q->debug_rssi, agc_crcf_get_signal_level(_q->sigdet));
#endif
    float rxx_mag = cabsf(_q->rxx);

    float threshold = (_q->rxx_thresh)*(_q->autocorr_length);

    if (rxx_mag > threshold) {
        // wait for auto-correlation to peak before changing state
        if (rxx_mag > _q->rxx_mag_max) {
            _q->rxx_mag_max = rxx_mag;
            return;
        }

        // estimate CFO
        _q->nu_hat = cargf(_q->rxx);
        if (_q->nu_hat >  M_PI/2.0f) _q->nu_hat -= M_PI;
        if (_q->nu_hat < -M_PI/2.0f) _q->nu_hat += M_PI;
        _q->nu_hat *= 4.0f / (float)(_q->num_subcarriers);

#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
        printf("rxx = |%12.8f| arg{%12.8f}\n", cabsf(_q->rxx),cargf(_q->rxx));
        printf("nu_hat =  %12.8f\n", _q->nu_hat);
#endif

        nco_crcf_set_frequency(_q->nco_rx, _q->nu_hat);
        _q->state = OFDMOQAMFRAME64SYNC_STATE_PLCPLONG0;

        _q->g = agc_crcf_get_gain(_q->sigdet);

#if DEBUG_OFDMOQAMFRAME64SYNC_PRINT
        printf("gain : %f\n", _q->g);
#endif
        _q->timer=0;
    }
}