SDR (Software Defined Radio) » OsmoSDR

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <math.h>

#include <portaudio.h>

#include "serial.h"

#include "utils.h"

struct SweepState {

	int serialFd;

	int settleTime;

	int sampleTime;

	uint64_t freq;

	double acc;

	double num;

	double start;

	double stop;

};

static int printSyntax()

{

	fprintf(stderr, "Error: Invalid command line!\n\n"

		"syntax: sdr-sweep /dev/ttyUSB0 start stop"

		"  - start = start frequency in MHz, e.g 88.5\n"

		"  - stop = stop frequency in MHz, e.g. 108\n"

		"frequency range of OsmoSDR is 64MHz - 1700MHz\n");

	return EXIT_FAILURE;

}

static void setFreq(int fd, uint64_t freq)

{

	char str[128];

	char* c;

	char str2[2] = { '\0', '\0' };

	while(serialGetS(fd, str, sizeof(str), 1) >= 0)

		;

	sprintf(str, "tuner.freq=%llu\r", freq);

	for(c = str; *c != '\0'; c++) {

		serialPutC(fd, *c);

		if(*c == '\r')

			str2[0] = '\n';

		else str2[0] = *c;

		if(serialExpect(fd, str2, 1) < 0) {

			serialPutC(fd, *c);

			if(serialExpect(fd, str2, 1) < 0) {

				fprintf(stderr, "serial port broken (%d = %c)\n", *c, *c);

				return;

			}

		}

	}

}

static int audioCallback(const void* inputBuffer, void* outputBuffer,

	unsigned long framesPerBuffer,

	const PaStreamCallbackTimeInfo* timeInfo,

	PaStreamCallbackFlags statusFlags,

	void* userData)

{

	struct SweepState* state = (struct SweepState*)userData;

	int i;

	const int16_t* input = (const int16_t*)inputBuffer;

	uint8_t c;

	double v;

	int max;

	//fprintf(stderr, "block %lu\n", framesPerBuffer);

	while(serialGetC(state->serialFd, &c, 0) >= 0)

		//fprintf(stderr, "%c", c);

		;

	if(state->settleTime > 0) {

		state->settleTime -= framesPerBuffer;

		if(state->settleTime <= 0) {

			state->sampleTime = 100000;

			state->acc = 0.0;

			state->num = 0.0;

		}

		return 0;

	}

	if(state->sampleTime > 0) {

		max = 0;

		for(i = 0; i < framesPerBuffer; i++) {

			if(abs(*input) > max)

				max = abs(*input);

			v = *input / 32768.0;

			state->acc += v * v;

			input++;

			if(abs(*input) > max)

				max = abs(*input);

			v = *input / 32768.0;

			state->acc += v * v;

			input++;

			state->num += 2;

		}

		//fprintf(stderr, "-> %d\n", max);

		state->sampleTime -= framesPerBuffer;

		if(state->sampleTime <= 0) {

			printf("%.1f\t%.1f\n", state->freq / 1000000.0, 20.0 * log10(sqrt(state->acc / state->num)));

			fflush(stdout);

			state->freq += 100000;

			setFreq(state->serialFd, state->freq);

			state->settleTime = 500000;

		}

	}

	return 0;

}

static PaStream* audioOpen(struct SweepState* state)

{

	int numDevices;

	const PaDeviceInfo* deviceInfo;

	PaError err;

	int i;

	int dev = -1;

	PaStream* stream = NULL;

	PaStreamParameters inputParameters;

	err = Pa_Initialize();

	if(err != paNoError)

		goto error_noinit;

	numDevices = Pa_GetDeviceCount();

	if(numDevices < 0) {

		err = numDevices;

		goto error;

	}

	for(i = 0; i < numDevices; i++) {

		deviceInfo = Pa_GetDeviceInfo(i);

		fprintf(stderr, "#%02d -> [%s]\n", i, deviceInfo->name);

		if(strncmp(deviceInfo->name, "OsmoSDR", 7) == 0)

			dev = i;

	}

	if(dev < 0) {

		fprintf(stderr, "OsmoSDR not found!\n");

		Pa_Terminate();

		return NULL;

	}

	fprintf(stderr, "Using device #%02d (sample rate %.0f Hz)\n", dev, Pa_GetDeviceInfo(dev)->defaultSampleRate);

	bzero(&inputParameters, sizeof(inputParameters));

	inputParameters.channelCount = 2;

	inputParameters.device = dev;

	inputParameters.hostApiSpecificStreamInfo = NULL;

	inputParameters.sampleFormat = paInt16;

	inputParameters.suggestedLatency = Pa_GetDeviceInfo(dev)->defaultHighInputLatency ;

	inputParameters.hostApiSpecificStreamInfo = NULL;

	err = Pa_OpenStream(&stream, &inputParameters, NULL, Pa_GetDeviceInfo(dev)->defaultSampleRate, 20000,

		paClipOff | paDitherOff, audioCallback, state);

	if(err != paNoError)

		goto error_noinit;

	err = Pa_StartStream(stream);

	if(err != paNoError)

		goto error_noinit;

	return stream;

error:

	Pa_Terminate();

error_noinit:

	fprintf(stderr, "PortAudio error: %s\n", Pa_GetErrorText(err));

	return NULL;

}

static void audioClose(PaStream* stream)

{

	PaError err;

	err = Pa_StopStream(stream);

	if(err != paNoError)

		fprintf(stderr, "PortAudio error: %s\n", Pa_GetErrorText(err));

	err = Pa_CloseStream(stream);

	if(err != paNoError)

		fprintf(stderr, "PortAudio error: %s\n", Pa_GetErrorText(err));

	err = Pa_Terminate();

	if(err != paNoError)

		fprintf(stderr, "PortAudio error: %s\n", Pa_GetErrorText(err));

}

int main(int argc, char* argv[])

{

	HANDLE fd;

	PaStream* stream;

	struct SweepState state;

	if(argc < 4)

		return printSyntax();

	if((fd = serialOpen(argv[1])) == INVALID_HANDLE_VALUE)

		return EXIT_FAILURE;

	memset(&state, 0x00, sizeof(struct SweepState));

	state.serialFd = fd;

	state.settleTime = 100000;

	state.start = atof(argv[2]);

	state.stop = atof(argv[3]);

	state.freq = state.start * 1000000.0;

	serialPutS(fd, "\r\r\rtuner.init!\r\r\r");

	setFreq(fd, state.freq);

	if((stream = audioOpen(&state)) == NULL) {

		serialClose(fd);

		return EXIT_FAILURE;

	}

	fprintf(stderr, "sweep running...\n");

	while(1) {

		sleep(1);

		if(state.freq > state.stop * 1000000.0)

			break;

		fprintf(stderr, "...%.1f MHz...\n", state.freq / 1000000.0);

	}

	audioClose(stream);

	serialClose(fd);

	return EXIT_FAILURE;

}