extend frequency range to 10kHz

nanovna-v2 · May 7, 2020 · 7980406 · 7980406
1 parent 47b2b83
commit 7980406
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Showing 4 changed files with 136 additions and 13 deletions.
diff --git a/common.hpp b/common.hpp
@@ -42,7 +42,7 @@ typedef int64_t freqHz_t;
 #define PLATFORM_NAME "BARE METAL"
 
 
-#define FREQUENCY_MIN 50000
+#define FREQUENCY_MIN 10000
 #define FREQUENCY_MAX 4400000000
 #define SWEEP_POINTS_MIN 2
 #define SWEEP_POINTS_MAX 201

diff --git a/main2.cpp b/main2.cpp
@@ -224,9 +224,37 @@ void adf4350_update(freqHz_t freqHz) {
 	synthesizers::adf4350_set(adf4350_rx, freqHz + lo_freq, adf4350_freqStep);
 }
 
+// automatically set IF frequency depending on rf frequency and board parameters
+void updateIFrequency(freqHz_t txFreqHz) {
+	// adf4350 freq step and thus IF frequency must be a divisor of the crystal frequency
+	if(xtalFreqHz == 20000000 || xtalFreqHz == 40000000) {
+		// 6.25/12.5kHz IF
+		if(txFreqHz >= 100000) {
+			lo_freq = 12500;
+			adf4350_freqStep = 12500;
+			vnaMeasurement.setCorrelationTable(sinROM24x2, 48);
+		} else {
+			lo_freq = 6250;
+			adf4350_freqStep = 6250;
+			vnaMeasurement.setCorrelationTable(sinROM48x1, 48);
+		}
+	} else {
+		// 6.0/12.0kHz IF
+		if(txFreqHz >= 100000) {
+			lo_freq = 12000;
+			adf4350_freqStep = 12000;
+			vnaMeasurement.setCorrelationTable(sinROM25x2, 50);
+		} else {
+			lo_freq = 6000;
+			adf4350_freqStep = 6000;
+			vnaMeasurement.setCorrelationTable(sinROM50x1, 50);
+		}
+	}
+}
 
 // set the measurement frequency including setting the tx and rx synthesizers
 void setFrequency(freqHz_t freqHz) {
+	updateIFrequency(freqHz);
 	if(freqHz > 2500000000)
 		rfsw(RFSW_BBGAIN, RFSW_BBGAIN_GAIN(2));
 	else if(freqHz > 140000000)
@@ -802,18 +830,6 @@ void measurement_setup() {
 	vnaMeasurement.nPeriods = MEASUREMENT_NPERIODS_NORMAL;
 	vnaMeasurement.init();
 
-	// adf4350 freq step and thus IF frequency must be a divisor of the crystal frequency
-	if(xtalFreqHz == 20000000 || xtalFreqHz == 40000000) {
-		// 12.5kHz IF
-		lo_freq = 12500;
-		adf4350_freqStep = 12500;
-		vnaMeasurement.setCorrelationTable(sinROM24x2, 48);
-	} else {
-		// 12.0kHz IF
-		lo_freq = 12000;
-		adf4350_freqStep = 12000;
-		vnaMeasurement.setCorrelationTable(sinROM25x2, 50);
-	}
 	setVNASweepToUI();
 }
 

diff --git a/sin_rom.cpp b/sin_rom.cpp
@@ -7,6 +7,108 @@
 // that is a convolution between a rect with width of one IF period
 // and a gaussian window.
 
+const int16_t sinROM50x1[100] = {
+32767, 0,
+32509, -4107,
+31738, -8149,
+30466, -12062,
+28714, -15786,
+26509, -19260,
+23886, -22431,
+20886, -25247,
+17557, -27666,
+13952, -29648,
+10126, -31163,
+6140, -32187,
+2057, -32702,
+-2057, -32702,
+-6140, -32187,
+-10126, -31163,
+-13952, -29648,
+-17557, -27666,
+-20886, -25247,
+-23886, -22431,
+-26509, -19260,
+-28714, -15786,
+-30466, -12062,
+-31738, -8149,
+-32509, -4107,
+-32767, 0,
+-32509, 4107,
+-31738, 8149,
+-30466, 12062,
+-28714, 15786,
+-26509, 19260,
+-23886, 22431,
+-20886, 25247,
+-17557, 27666,
+-13952, 29648,
+-10126, 31163,
+-6140, 32187,
+-2057, 32702,
+2057, 32702,
+6140, 32187,
+10126, 31163,
+13952, 29648,
+17557, 27666,
+20886, 25247,
+23886, 22431,
+26509, 19260,
+28714, 15786,
+30466, 12062,
+31738, 8149,
+32509, 4107};
+
+const int16_t sinROM48x1[96] = {
+32767, 0,
+32487, -4277,
+31650, -8481,
+30273, -12539,
+28377, -16383,
+25996, -19947,
+23170, -23170,
+19947, -25996,
+16384, -28377,
+12539, -30273,
+8481, -31650,
+4277, -32487,
+0, -32767,
+-4277, -32487,
+-8481, -31650,
+-12539, -30273,
+-16383, -28377,
+-19947, -25996,
+-23170, -23170,
+-25996, -19947,
+-28377, -16383,
+-30273, -12539,
+-31650, -8481,
+-32487, -4277,
+-32767, 0,
+-32487, 4277,
+-31650, 8481,
+-30273, 12539,
+-28377, 16384,
+-25996, 19947,
+-23170, 23170,
+-19947, 25996,
+-16384, 28377,
+-12539, 30273,
+-8481, 31650,
+-4277, 32487,
+0, 32767,
+4277, 32487,
+8481, 31650,
+12539, 30273,
+16384, 28377,
+19947, 25996,
+23170, 23170,
+25996, 19947,
+28377, 16384,
+30273, 12539,
+31650, 8481,
+32487, 4277};
+
 const int16_t sinROM25x2[100] = {
 464, 0,
 1018, -261,

diff --git a/sin_rom.hpp b/sin_rom.hpp
@@ -1,6 +1,11 @@
 #pragma once
 #include <stdint.h>
 
+// period = 50; 1 period
+extern const int16_t sinROM50x1[100];
+
+// period = 48, 1 period
+extern const int16_t sinROM48x1[96];
 
 // period = 25; 2 periods
 extern const int16_t sinROM25x2[100];