initial
Dependencies: mbed BSP_DISCO_F746NG mbed-dsp
signal_processing.cpp
- Committer:
- justenmg
- Date:
- 2020-03-04
- Revision:
- 4:99de9b4005d2
- Parent:
- 3:51e15bd15778
- Child:
- 5:a658cda1d619
File content as of revision 4:99de9b4005d2:
/** ****************************************************************************** * @file signal_processing.c * @author Brian Mazzeo * @date 2020 * @brief This file provides a set of code for signal processing in 487. * Parts are taken from example code from STMIcroelectronics ****************************************************************************** * @attention * This code was specifically developed for BYU ECEn 487 course * Introduction to Digital Signal Processing. * * ****************************************************************************** */ #include "mbed.h" #include "stm32746g_discovery_lcd.h" #include "arm_math.h" #include "arm_const_structs.h" #include "filter_coefficients.h" #include "our_filter.h" #include "windowed.h" #include "signal_processing.h" /* ---------------------------------------------------------------------- ** Defines for signal processing ** ------------------------------------------------------------------- */ #define AUDIO_BLOCK_SAMPLES ((uint32_t)128) // Number of samples (L and R) in audio block (each samples is 16 bits) #define BUFFER_LENGTH (WIN_NUM_TAPS + AUDIO_BLOCK_SAMPLES - 1) #define FFT_BUFFER_LENGTH 2048 /* For Lab Exercise */ #define Lab_Execution_Type 3 float32_t lState[NUM_TAPS + AUDIO_BLOCK_SAMPLES - 1]; float32_t rState[NUM_TAPS + AUDIO_BLOCK_SAMPLES - 1]; float32_t l_buf[BUFFER_LENGTH]; float32_t r_buf[BUFFER_LENGTH]; arm_fir_instance_f32 filter_left; arm_fir_instance_f32 filter_right; float32_t fft_buf[FFT_BUFFER_LENGTH]; float32_t fft_of_filter[FFT_BUFFER_LENGTH]; /* FUNCTION DEFINITIONS BELOW */ /** * @brief Initialize filter structures to be used in loops later * @retval None */ void initalize_signal_processing(void) { switch (Lab_Execution_Type) { case 0: // Passthrough case break; case 1: // FIR case (ARM) arm_fir_init_f32(&filter_left, NUM_TAPS, (float32_t *)&Filter_coeffs, (float32_t *)&lState, AUDIO_BLOCK_SAMPLES); arm_fir_init_f32(&filter_right, NUM_TAPS, (float32_t *)&Filter_coeffs, (float32_t *)&rState, AUDIO_BLOCK_SAMPLES); break; case 2: // FIR case (student) arm_fir_init_f32(&filter_left, OUR_NUM_TAPS, (float32_t *)&our_Filter_coeffs, (float32_t *)&lState, AUDIO_BLOCK_SAMPLES); arm_fir_init_f32(&filter_right, OUR_NUM_TAPS, (float32_t *)&our_Filter_coeffs, (float32_t *)&rState, AUDIO_BLOCK_SAMPLES); break; case 3: // FFT Overlap-add filter_conv_init(); break; case 4: // FFT Overlap-add filter_fft_init(); break; case 5: // FFT Overlap-add with real-imag efficiency filter_fft_init(); break; case 6: // OS FFT RI filter_fft_init(); break; } } /** * @brief Process audio channel signals * @param L_channel_in: Pointer to Left channel data input (float32_t) * @param R_channel_in: Pointer to Right channel data input (float32_t) * @param L_channel_out: Pointer to Left channel data output (float32_t) * @param R_channel_out: Pointer to Right channel data output (float32_t) * @param Signal_Length: length of data to process * @retval None */ void process_audio_channel_signals(float32_t* L_channel_in, float32_t* R_channel_in, float32_t* L_channel_out, float32_t* R_channel_out, uint16_t Signal_Length) { char buf[70]; BSP_LCD_SetFont(&Font8); BSP_LCD_SetTextColor(LCD_COLOR_CYAN); sprintf(buf, "Processing Signals" ); BSP_LCD_DisplayStringAt(0, 200, (uint8_t *) buf, LEFT_MODE); switch(Lab_Execution_Type) { case 0: // Passthrough case arm_copy_f32(L_channel_in, L_channel_out, Signal_Length); arm_copy_f32(R_channel_in, R_channel_out, Signal_Length); break; case 1: // FIR case (ARM) arm_fir_f32(&filter_left, L_channel_in, L_channel_out, Signal_Length); arm_fir_f32(&filter_right, R_channel_in, R_channel_out, Signal_Length); break; case 2: // FIR case (student) arm_fir_f32(&filter_left, L_channel_in, L_channel_out, Signal_Length); arm_fir_f32(&filter_right, R_channel_in, R_channel_out, Signal_Length); break; case 3: // OA CONV filter_OA_CONV(l_buf, L_channel_in, L_channel_out, Signal_Length, BUFFER_LENGTH); filter_OA_CONV(r_buf, R_channel_in, R_channel_out, Signal_Length, BUFFER_LENGTH); break; case 4: // OA FFT Overlap-add break; case 5: // FFT Overlap-add with real-imag efficiency break; case 6: // OS FFT RI break; } /* Change font back */ BSP_LCD_SetFont(&Font16); } //buffer: pointer to the storage buffer for the filter output //buf_length: the length of the storage buffer (len_filter + len_batch - 1) void filter_OA_CONV(float32_t* overlap_buffer, float32_t* d_in, float32_t* d_out, uint16_t sig_length, uint16_t buf_length) { float32_t* data_sample = d_in; float32_t* filter_sample = win_filter_coeffs; float32_t result = 0; uint16_t conv_length = 0; //convolve and save to buffer /* for(uint16_t shift = 0; shift < buf_length; shift++) { //shift if(shift < sig_length) { conv_length = shift + 1; } else if(shift >= sig_length && shift < WIN_NUM_TAPS) { conv_length = sig_length; } else if(shift >= WIN_NUM_TAPS) { conv_length = sig_length - (shift - WIN_NUM_TAPS + 1); } result = 0; //multiply-add for(int i=0; i<conv_length; i++) { result += (filter_sample[i]) * (data_sample[shift - i]); } // save to the buffer overlap_buffer[shift] += result; } */ for(int i=0; i < buf_length; i++) { if(i < sig_length) { overlap_buffer[i] = data_sample[i]; } else { overlap_buffer[i] = 0; } } //copy from buffer to d_out, shift buffer, zero pad for(int i=0; i < buf_length; i++) { if(i < sig_length) { d_out[i] = overlap_buffer[i]; overlap_buffer[i] = overlap_buffer[i+sig_length]; } else { overlap_buffer[i] = 0; } } return; } void filter_OA_FFT(float32_t* buffer_begin, float32_t* buffer_head, uint16_t buffer_head_idx, float32_t* d_in, float32_t* d_out, uint16_t sig_length, uint16_t buf_length) { /*float32_t* data_sample = d_in+sig_length-1; float32_t* filter_sample = win_filter_coeffs; float32_t result = 0; float32_t* buffer_data_location = buffer_head; for(uint16_t i = 0; i < FFT_BUFFER_LENGTH; i++) { fft_buf[i] = d_in[i]; } arm_cfft_f32(&arm_cfft_sR_f32_len1024, fft_buf, 0, 1); for(uint16_t i = 0; i < FFT_BUFFER_LENGTH; i++) { fft_buf[i] = fft_buf[i]*fft_of_filter[i]; } arm_cfft_f32(&arm_cfft_sR_f32_len1024, fft_buf, 1, 1); // save to buffer for(uint16_t i = 0; i < buf_length; i++) { // save to the buffer *buffer_data_location += fft_buf[i]; //increment, looping back to beginning of buffer if(buffer_data_location == (buffer_begin + buf_length - 1)) { buffer_data_location = buffer_begin; } else { buffer_data_location++; } } //copy from buffer to d_out buffer_data_location = buffer_head; for(int i=0; i < sig_length; i++) { d_out[i] = *buffer_data_location; *buffer_data_location = 0; //increment, looping back to beginning of buffer if(buffer_data_location + i == (buffer_begin + buf_length - 1)) { buffer_data_location = buffer_begin; } else { buffer_data_location++; } }*/ return; } void filter_OA_FFT_RI(float32_t* buffer_begin, float32_t* buffer_head, uint16_t buffer_head_idx, float32_t* d_in, float32_t* d_out, uint16_t sig_length, uint16_t buf_length) { return; } void filter_OS_FFT_RI(float32_t* buffer_begin, float32_t* buffer_head, uint16_t buffer_head_idx, float32_t* d_in, float32_t* d_out, uint16_t sig_length, uint16_t buf_length) { return; } void filter_conv_init() { for(int i=0; i < BUFFER_LENGTH; i++) { l_buf[i] = 0; r_buf[i] = 0; } return; } void filter_fft_init() { for(int i=0; i < FFT_BUFFER_LENGTH; i++) { if(i < WIN_NUM_TAPS) { fft_of_filter[i] = win_filter_coeffs[i]; } else { fft_of_filter[i] = 0; } } arm_cfft_f32(&arm_cfft_sR_f32_len1024, fft_of_filter, 0, 1); return; }