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Introduction to
Digital Voice and DMRReilly Grant
K6YAP
Digital Voice
timevoltage
Input signal
vo
lta
ge
time
Carrier
Amplitude Modulation Frequency Modulation
time voltage
0 0
1 1
2 2
3 3
4 4
5 3
6 2
7 1
8 0
⁞ ⁞
time
vo
lta
ge
value binary
0 000
1 001
2 010
3 011
4 100
3 011
2 010
1 001
0 000
⁞ ⁞
000001010011100011010001000
010110110101
0101110011001010
Original bit stream:
Compressed bit stream:
Error correction added:
Digital Modulation
time
vo
lta
ge
Bit stream: 1101101
tim
e
frequency
time
vo
lta
ge
Bit stream: 1101101
tim
e
frequency
Bit stream: 101100101001111000
tim
e
frequency
symbol frequency
00 +648 kHz
01 +1,944 kHz
10 -648 kHz
11 -1,944 kHz
DMR
Repeater station
TX: 444.35 MHzRX: 449.35 MHz
TX: 449.35 MHz
RX: 444.35 MHz
Handheld station
CC1
CC2
CC2
CC1
CC2
Same frequency
Different color code
TG31075
TG31075
TG31064
TG31064
TG31064
Source: ETSI TS 102 361-1 V2.5.1 (2017-10)
Source: ETSI TS 102 361-1 V2.5.1 (2017-10)
Source: ETSI TS 102 361-1 V2.5.1 (2017-10)
TG31075
TS2
TG31075
TS2
TG31064
TS1
TG31064
TS1
TG31064
TS1
Linked Repeaters
Internet
Site A
Site B
Site C
Site A Site B
network linkTG93
TS1
TG2
TS2
TG2
TS2
TG93
TS2
WW6BAY WA6YCZ
N6AMGKK6USZ
TG1: 91064
TG2: 91075
TG1: 93, 3106, 31064, 31065,
31075, 31096, 310604
TG2: 97150
TG1: 93, 3106, 31065,
31075, 31096, 310604
TG2: 97150
TG1: 3131, 31679
TG2: 31064, 31068, 31075,
110670
Programming
Questions?