Add calculator for valid symbol lengths.

misc/modes.go

@@ -0,0 +1,33 @@
+// Calculates:
+// Valid symbol lengths.
+// Sample rate to achieve the symbol length.
+// Number of channels covered.
+// Excess bandwidth outside of the captured channels.
+
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+const (
+	DataRate     = 32768
+	ChannelWidth = 196568
+
+	// Valid sample rates fall in one of two bands:
+	// http://cgit.osmocom.org/rtl-sdr/tree/src/librtlsdr.c#n1069
+	LowerMin = 225e3
+	LowerMax = 300e3
+	UpperMin = 900e3
+	UpperMax = 3.2e6
+)
+
+func main() {
+	for symbolLength := 1; symbolLength < int(math.Ceil(UpperMax/DataRate)); symbolLength++ {
+		sampleRate := symbolLength * DataRate
+		if (LowerMin < sampleRate && sampleRate <= LowerMax) || (UpperMin < sampleRate && sampleRate <= UpperMax) {
+			fmt.Printf("SymbolLength:%d SampleRate:%d Channels:%d ExcessBandwidth:%d\n", symbolLength, sampleRate, sampleRate/ChannelWidth, sampleRate%ChannelWidth)
+		}
+	}
+}