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?