optionally store baud rate in rx metadata

some transmitters can support different baud rates. storing baud rate in
each beacon can help with rx signal analysis

src/main/java/ru/r2cloud/jradio/BeaconInputStream.java

@@ -69,7 +69,19 @@ private T readProtocolv2() throws Exception {
 	}
 
 	private T readProtocolv3() throws Exception {
-		T result = readProtocolv2();
+		int length = is.readInt();
+		byte[] raw = new byte[length];
+		is.readFully(raw);
+		T result = clazz.getDeclaredConstructor().newInstance();
+		result.readExternal(raw);
+		result.setBeginMillis(is.readLong());
+		result.setBeginSample(is.readLong());
+		RxMetadata meta = new RxMetadata();
+		meta.setRssi(is.readFloat());
+		meta.setSnr(is.readFloat());
+		meta.setFrequencyError(is.readLong());
+		meta.setBaud(is.readInt());
+		result.setRxMeta(meta);
 		result.setEndSample(is.readLong());
 		return result;
 	}

src/main/java/ru/r2cloud/jradio/BeaconOutputStream.java

@@ -42,10 +42,16 @@ public void write(Beacon beacon) throws IOException {
 			} else {
 				dos.writeLong(0);
 			}
+			if (meta.getBaud() != null) {
+				dos.writeInt(meta.getBaud());
+			} else {
+				dos.writeInt(0);
+			}
 		} else {
 			dos.writeFloat(0.0f);
 			dos.writeFloat(0.0f);
 			dos.writeLong(0);
+			dos.writeInt(0);
 		}
 		dos.writeLong(beacon.getEndSample());
 	}

src/main/java/ru/r2cloud/jradio/RxMetadata.java

@@ -5,6 +5,15 @@ public class RxMetadata {
 	private Float rssi;
 	private Float snr;
 	private Long frequencyError;
+	private Integer baud;
+
+	public Integer getBaud() {
+		return baud;
+	}
+
+	public void setBaud(Integer baud) {
+		this.baud = baud;
+	}
 
 	public Float getRssi() {
 		return rssi;
@@ -41,7 +50,10 @@ public String toString() {
 			result.append(" snr=").append(snr);
 		}
 		if (frequencyError != null) {
-			result.append("frequencyError=").append(frequencyError);
+			result.append(" frequencyError=").append(frequencyError);
+		}
+		if (baud != null) {
+			result.append("baud=").append(baud);
 		}
 		result.append(" ]");
 		return result.toString();

src/main/java/ru/r2cloud/jradio/sink/SnrCalculator.java

@@ -87,7 +87,10 @@ public static void enrichSnr(FloatInput source, List<Beacon> beacons, long bandw
 			}
 
 			if (snrTotal > 0) {
-				RxMetadata meta = new RxMetadata();
+				RxMetadata meta = cur.getRxMeta();
+				if (meta == null) {
+					meta = new RxMetadata();
+				}
 				meta.setSnr(sumSnr / snrTotal);
 				cur.setRxMeta(meta);
 			}

src/test/java/ru/r2cloud/jradio/BeaconInputStreamTest.java

@@ -27,6 +27,7 @@ public void testReadWrite() throws Exception {
 		meta.setRssi(1.23f);
 		meta.setSnr(1.22f);
 		meta.setFrequencyError(1001l);
+		meta.setBaud(9600);
 		data.setRxMeta(meta);
 		data.setEndSample(2L);
 
@@ -43,6 +44,7 @@ public void testReadWrite() throws Exception {
 		assertEquals(data.getRxMeta().getRssi(), actual.getRxMeta().getRssi(), 0.0001);
 		assertEquals(data.getRxMeta().getSnr(), actual.getRxMeta().getSnr(), 0.0001);
 		assertEquals(data.getRxMeta().getFrequencyError(), actual.getRxMeta().getFrequencyError());
+		assertEquals(data.getRxMeta().getBaud(), actual.getRxMeta().getBaud());
 		assertEquals(data.getEndSample(), actual.getEndSample());
 		assertArrayEquals(data.getRawData(), actual.getRawData());
 		assertFalse(bis.hasNext());