1#define ST2095_MAX_PEAK -9.5    // dB
2#define ST2095_HPFC     10.0    // Highpass filter cutoff in Hz
3#define ST2095_LPFC     22400.0 // Lowpass filter cutoff in Hz
4
5typedef struct
6{
7  float maxAmp;
8  int samplesPerPeriod;
9  int randStep;
10  int randMax;
11  int seed;
12  float scaleFactor;
13  float w0t;
14  float k;
15  float k2;
16  float LpFc;
17  // biquad coefficients
18  float hp1_a1, hp1_a2;
19  float hp1_b0, hp1_b1, hp1_b2;
20  float hp2_a1, hp2_a2;
21  float hp2_b0, hp2_b1, hp2_b2;
22  float lp1_a1, lp1_a2;
23  float lp1_b0, lp1_b1, lp1_b2;
24  float lp2_a1, lp2_a2;
25  float lp2_b0, lp2_b1, lp2_b2;
26  // delay-line variables for bandpass filter
27  float hp1w1, hp1w2;
28  float hp2w1, hp2w2;
29  float lp1w1, lp1w2;
30  float lp2w1, lp2w2;
31  // delay-line variables for pink filter network
32  float lp1, lp2, lp3, lp4, lp5, lp6;
33  // statistics accumulator
34  float accum;
35} st2095_noise_t;
36
37void initialize_st2095_noise( st2095_noise_t *st2095, int sample_rate );
38float generate_st2095_noise_sample( st2095_noise_t *st2095 );
39
40void reset_st2095_noise_measurement( st2095_noise_t *st2095 );
41float compute_st2095_noise_measurement( st2095_noise_t *st2095, int period );
42