diff --git a/src/main.c b/src/main.c
index 6c67be0..536e204 100644
--- a/src/main.c
+++ b/src/main.c
@@ -96,6 +96,14 @@ static int agc = 0;
 
 #define PSU_PIN 23
 
+static uint32_t rnd = 0;
+
+inline static uint32_t rnd_next()
+{
+	rnd = rnd * 0x41c64e6d + 12345;
+	return rnd;
+}
+
 static void bias_init(int in_pin, int out_pin)
 {
 	gpio_disable_pulls(in_pin);
@@ -264,7 +272,7 @@ static void adder_init()
 	pio_sm_set_enabled(pio1, 3, true);
 }
 
-inline static float lo_round_freq(size_t bits, float req_freq)
+inline static double lo_round_freq(size_t bits, double req_freq)
 {
 	const double step_hz = (double)CLK_SYS_HZ / bits;
 	return round(req_freq / step_hz) * step_hz;
@@ -272,7 +280,7 @@ inline static float lo_round_freq(size_t bits, float req_freq)
 
 static void lo_generate(uint32_t *buf, size_t len, double freq, unsigned phase)
 {
-	unsigned step = ((double)UINT_MAX + 1.0) / (double)CLK_SYS_HZ * freq;
+	unsigned step = (UINT_MAX + 1.0) / CLK_SYS_HZ * freq;
 	unsigned accum = phase;
 
 	for (size_t i = 0; i < len; i++) {
@@ -280,10 +288,7 @@ static void lo_generate(uint32_t *buf, size_t len, double freq, unsigned phase)
 
 		for (int j = 0; j < 32; j++) {
 #if LO_DITHER
-			int n0 = rand() - RAND_MAX / 2;
-			int n1 = rand() - RAND_MAX / 2;
-			int noise = (n0 + n1) / 2;
-
+			int noise = (rnd_next() >> 3) - (rnd_next() >> 3);
 			bits |= (accum + noise) >> 31;
 #else
 			bits |= accum >> 31;
@@ -296,9 +301,9 @@ static void lo_generate(uint32_t *buf, size_t len, double freq, unsigned phase)
 	}
 }
 
-static float rx_lo_init(double req_freq)
+static double rx_lo_init(double req_freq)
 {
-	float freq = lo_round_freq(LO_WORDS * 32, req_freq);
+	double freq = lo_round_freq(LO_WORDS * 8, req_freq);
 
 	lo_generate(lo_cos, LO_WORDS, freq, COS_PHASE);
 	lo_generate(lo_sin, LO_WORDS, freq, SIN_PHASE);
@@ -306,10 +311,10 @@ static float rx_lo_init(double req_freq)
 	return freq;
 }
 
-static float tx_fsk_lo_init(float req_freq, float separation)
+static double tx_fsk_lo_init(double req_freq, double separation)
 {
-	float hi = lo_round_freq(LO_WORDS * 32, req_freq + separation / 2);
-	float lo = lo_round_freq(LO_WORDS * 32, hi - separation);
+	double hi = lo_round_freq(LO_WORDS * 8, req_freq + separation / 2);
+	double lo = lo_round_freq(LO_WORDS * 8, hi - separation);
 
 	lo_generate(lo_cos, LO_WORDS, hi, COS_PHASE);
 	lo_generate(lo_sin, LO_WORDS, lo, SIN_PHASE);
@@ -364,7 +369,7 @@ static const uint32_t samp_insn[] __attribute__((__aligned__(16))) = {
 
 static uint32_t null, one = 1;
 
-static float rf_rx_start(int rx_pin, int bias_pin, float freq, int frac_num, int frac_denom)
+static double rf_rx_start(int rx_pin, int bias_pin, double freq, int frac_num, int frac_denom)
 {
 	dma_ch_rx = dma_claim_unused_channel(true);
 	dma_ch_cp = dma_claim_unused_channel(true);
@@ -472,7 +477,7 @@ static float rf_rx_start(int rx_pin, int bias_pin, float freq, int frac_num, int
 	bias_init(rx_pin, bias_pin);
 	adder_init();
 
-	float actual = rx_lo_init(freq);
+	double actual = rx_lo_init(freq);
 
 	dma_channel_start(dma_ch_rx);
 	dma_channel_start(dma_ch_samp_trig);
@@ -782,9 +787,9 @@ static void __unused plot_IQ(int I, int Q)
 	}
 }
 
-static void do_rx(int rx_pin, int bias_pin, float freq, char mode)
+static void do_rx(int rx_pin, int bias_pin, double freq, char mode)
 {
-	float actual = rf_rx_start(rx_pin, bias_pin, freq, 1, CLK_SYS_HZ / BANDWIDTH);
+	double actual = rf_rx_start(rx_pin, bias_pin, freq, 1, CLK_SYS_HZ / BANDWIDTH);
 	sleep_us(100);
 
 	dma_ch_in_cos = dma_claim_unused_channel(true);
@@ -837,8 +842,8 @@ static void do_rx(int rx_pin, int bias_pin, float freq, char mode)
 				fflush(stdout);
 			} else {
 				/* Because AGC is kept 1 bit below to accomodate for jitter. */
-				float agc_frac = 2.0f * (float)agc / (float)INT_MAX;
-				float rssi = 10.0f * log10f(powf(agc_frac, 2));
+				double agc_frac = 2.0f * (double)agc / (double)INT_MAX;
+				double rssi = 10.0f * log10f(powf(agc_frac, 2));
 
 				for (int i = 0; i < IQ_BLOCK_LEN / 2; i += 2) {
 					int I = block[i] >> 8;
@@ -879,7 +884,7 @@ static void command(const char *cmd)
 {
 	static char tmp[83];
 	int n, x;
-	float f, g;
+	double f, g;
 
 	if (1 == sscanf(cmd, " help %[\a]", tmp)) {
 		puts("help             - this help");
@@ -912,25 +917,25 @@ static void command(const char *cmd)
 		return;
 	}
 
-	if (4 == sscanf(cmd, " rx %i %i %f %[\a]", &n, &x, &f, tmp)) {
+	if (4 == sscanf(cmd, " rx %i %i %lf %[\a]", &n, &x, &f, tmp)) {
 		do_rx(n, x, f, 'a');
 		return;
 	}
 
-	if (4 == sscanf(cmd, " brx %i %i %f %[\a]", &n, &x, &f, tmp)) {
+	if (4 == sscanf(cmd, " brx %i %i %lf %[\a]", &n, &x, &f, tmp)) {
 		do_rx(n, x, f, 'b');
 		return;
 	}
 
-	if (3 == sscanf(cmd, " bpsk %i %f %[\a]", &n, &f, tmp)) {
-		float actual = rx_lo_init(f);
+	if (3 == sscanf(cmd, " bpsk %i %lf %[\a]", &n, &f, tmp)) {
+		double actual = rx_lo_init(f);
 		printf("Frequency: %.0f\n", actual);
 
 		rf_tx_start(n);
 		puts("Transmitting, press ENTER to stop.");
 
 		bool phase = false;
-		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 32);
+		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 8);
 
 		while (true) {
 			int c = getchar_timeout_us(10000);
@@ -972,8 +977,8 @@ static void command(const char *cmd)
 		return;
 	}
 
-	if (4 == sscanf(cmd, " fsk %i %f %f %[\a]", &n, &f, &g, tmp)) {
-		g = lo_round_freq(LO_WORDS * 32, g);
+	if (4 == sscanf(cmd, " fsk %i %lf %lf %[\a]", &n, &f, &g, tmp)) {
+		g = lo_round_freq(LO_WORDS * 8, g);
 		f = tx_fsk_lo_init(f, g);
 		printf("Frequency: %.0f +/- %.f\n", f, g / 2.0f);
 
@@ -981,7 +986,7 @@ static void command(const char *cmd)
 		puts("Transmitting, press ENTER to stop.");
 
 		bool high = true;
-		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 32);
+		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 8);
 
 		while (true) {
 			int c = getchar_timeout_us(10000);
@@ -1024,15 +1029,15 @@ static void command(const char *cmd)
 		return;
 	}
 
-	if (3 == sscanf(cmd, " ook %i %f %[\a]", &n, &f, tmp)) {
-		float actual = rx_lo_init(f);
+	if (3 == sscanf(cmd, " ook %i %lf %[\a]", &n, &f, tmp)) {
+		double actual = rx_lo_init(f);
 		printf("Frequency: %.0f\n", actual);
 
 		rf_tx_start(n);
 		puts("Transmitting, press ENTER to stop.");
 
 		bool off = false;
-		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 32);
+		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 8);
 
 		while (true) {
 			int c = getchar_timeout_us(10000);
@@ -1063,12 +1068,12 @@ static void command(const char *cmd)
 		return;
 	}
 
-	if (5 == sscanf(cmd, " sweep %i %f %f %i %[\a]", &n, &f, &g, &x, tmp)) {
-		const float step_hz = (float)CLK_SYS_HZ / (LO_WORDS * 32);
-		const float start = roundf(f / step_hz) * step_hz;
-		const float stop = roundf(g / step_hz) * step_hz;
+	if (5 == sscanf(cmd, " sweep %i %lf %lf %i %[\a]", &n, &f, &g, &x, tmp)) {
+		const double step_hz = (double)CLK_SYS_HZ / (LO_WORDS * 8);
+		const double start = round(f / step_hz) * step_hz;
+		const double stop = round(g / step_hz) * step_hz;
 
-		int steps = roundf((stop - start) / step_hz);
+		int steps = round((stop - start) / step_hz);
 
 		for (int i = 0; i < LO_WORDS; i++)
 			lo_cos[i] = 0;
@@ -1080,7 +1085,7 @@ static void command(const char *cmd)
 			if ('\r' == c)
 				break;
 
-			float actual = rx_lo_init(start + i * step_hz);
+			double actual = rx_lo_init(start + i * step_hz);
 			printf("Frequency: %.0f\n", actual);
 		}
 
@@ -1091,7 +1096,7 @@ static void command(const char *cmd)
 
 	if (2 == sscanf(cmd, " noise %i %[\a]", &n, tmp)) {
 		for (int i = 0; i < LO_WORDS; i++)
-			lo_cos[i] = rand();
+			lo_cos[i] = rnd_next();
 
 		rf_tx_start(n);
 
@@ -1103,7 +1108,7 @@ static void command(const char *cmd)
 				break;
 
 			for (int i = 0; i < LO_WORDS; i++)
-				lo_cos[i] = rand();
+				lo_cos[i] = rnd_next();
 		}
 
 		rf_tx_stop();
@@ -1138,7 +1143,7 @@ int main()
 	}
 
 	printf("\nPuppet Online!\n");
-	printf("clk_sys = %10.6f MHz\n", (float)clock_get_hz(clk_sys) / MHZ);
+	printf("clk_sys = %10.6f MHz\n", (double)clock_get_hz(clk_sys) / MHZ);
 
 	queue_init(&iq_queue, IQ_BLOCK_LEN * sizeof(int16_t), 256);