SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[gsc12_grsc5_15]
Digital Radio Microphone in Japan
Studies for use in the 800 MHz band
in Japan
Shouhei Taniguchi (ARIB)
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Background
□ Application: broadcast and non-broadcast.
□ Popularization: the amount units are currently over the 2.4 million units as
general and various purpose and tends growth in Japan.
□ Operational problem: the interference between the each operation and a
lack of channel at urban crowded area has been more serious recently, the
analogue, however, had no way to solve these problems.
□ Latency Problem: The transparent codec that has less than 10ms latency
and 1/5 compression has been successfully developed and its ability has
been confirmed at official examination.
□ Transmission Reliability: To achieve the acceptable transmission error
caused by fading used to be hard in high frequency transmission over 1GHz,
or the propagation of wide band width over 500kHz, but the reliability of
transmission in 800MHz has been confirmed at the official examination.
□ Functional requirements: the secured transmission at concert and
conference, and remote and automatic operation by duplex communication.
□ Japanese Standardization: The digital radio law and the standard for general
purpose will be comprised based on this results in Japan.
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Digital Specification in Japan: The basics
□ Applications: general purpose for broadcast, concerts, conventions,
and various events at public halls, hotels, universities,
school, shopping malls, department stores, etc.
□ Frequency: 806.125MHz – 809.750MHz
□ Antenna Power: Less than 10mW
□ Modulation: QPSK, FSK, ASK, QAM ( without carrier modulation)
□ Transmission data speed: 128ksps
□ Audio performance: Dynamic Range more than 96dB,
Frequency up to 15kHz
□ Latency:
Less than 10msec
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
RF Characteristics of the prototype
1.00E-01
1.00E-02
ＢＥＲ
1.00E-03
1.00E-04
1.00E-05
Dynamic Range @BER=1e-6: 65dB
1.00E-06
1.00E-07
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Received Input Voltage[dBμV]
100m
10m
85
F.S.L
1m
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Maximum number of channels for simultaneous operation
Analogue
Minimum Spacing
250kHz
OBW
110kHz
6 channels
/4 MHz
810.000
809.750
809.500
809.250
809.000
808.750
808.500
808.250
808.000
807.750
807.500
807.250
807.000
806.750
806.500
806.250
806.125
Channel allocation have to be considered 3rd-order distortion at receiver
Digital
Minimum Spacing
375kHz
OBW
192kHz
10 channels
/4 MHz
810.000
809.750
809.500
809.250
809.000
808.750
808.500
808.250
808.000
807.750
807.500
807.250
807.000
806.750
806.500
806.250
806.125
Channel could be allocated with equal spacing
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Minimum distance between service areas to avoid interference
Definition of service area and interfered area
Service area: Whole operable area around a receiving antenna. (Radius is 60 m)
Interfered area: Area where operation of two radio microphones at the same frequency is impossible.
Assumed attenuation by obstacles is 15dB（Area where D/U for a radio microphone at the circumference cannot be
satisfied.
Comparison of no interfered area between Analogue vs. Digital
Analogue
Digital
Required D/U ratio: 40dB
干渉 エリア
Interfered
area
Radius: 240m
Required D/U ratio: 20 dB
Interference-free
distance: 180m
サービスエリア
Service
area
Radius: 60m
Minimum distance: 180m
Radio barrier
Attenuation: 15dB
Interfered
area
干渉 エリア
Radius: 90m
：
Service area
Radius: 60m
Interference-free
distance: 30m
Radio barrier
Attenuation: 15dB
Minimum distance: 30m
Comparison of interference-free distance between digital and analogue systems: 1/6
(30m/180m)
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Capable number of interference-free areas
Analogue
Digital
Minimum distance 180 m
Required D/U ratio: 40 dB
300 m
Number of interference-free areas: 7
Minimum distance 30 m
Required D/U ratio: 20 dB
150 m
Number of interference-free areas: 19
Possible number of interference-free areas in digital: 2.7 times (19/7)
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Capable number of interference-free areas
at Interleave allocation
Definition of service area
Analogue
and interfered area
Digital
Minimum distance 180 m
Interleave allocation: No
Coverage
Radius: 60m
Minimum distance 30 m
Interleave Allocation: Yes
Received Antenna
Not permitted area to use at
250kHz frequency interleave
allocation
Radius: 6m
300m
Number of interference-free areas: 7
150m
Service Area under basic channel
allocation
Increased Service Area under
basic channel allocation in Digital
Service Area under 250kHz
frequency interleave allocation
Number of interference-free areas: 31
Possible number of interference-free areas in digital: 4.4 times (31/7)
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Audio Quality 1: SNR
Audio response @ 1kHz sign wave input
Analogue
Digital
SNR is improved more than 20 dB
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Audio Quality 2: transparent codec
examination based on ITU-R BS1116-1
95% Confidence Interval
◆Mean Value
Original Source - Average of estimated sound
Quality
Estimated delay=3.7083msec
1.000
Female Vocals
Male Speech
Female Speech
Base Solo
Drums solo
0.500
Result as the
transparent
quality
0.000
-0.500
-1.000
-1.500
-2.000
-2.500
-3.000
-3.500
-4.000
192kbps 128kbps 192kbps 128kbps 192kbps 128kbps 192kbps 128kbps 192kbps 128kbps
To achieve the transparent quality for audio at Codec Delay :
3.7083ms and 192kbps
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
Audio Quality 3: transparent codec
examination based on ITU-R BS1116-1
Estimated delay: 5.5625msec
Original Source - Average of estimated sound Qualit
1.000
Female Vocals
Male Speech
Female Speech
95% Confidence Interval
Base Solo
◆Mean Value
Drums solo
0.500
Result as the
transparent
quality
0.000
-0.500
-1.000
-1.500
-2.000
-2.500
-3.000
-3.500
-4.000
128kbps
96kbps
128kbps
96kbps
128kbps
96kbps
128kbps
96kbps
128kbps
96kbps
To achieve the transparent quality for human voice at Codec Delay :
5.5625ms and 128kbps
SOURCE:
ARIB
TITLE:
Digital Radio Microphones in Japan
AGENDA ITEM:
GRSC-5 5.6
CONTACT:
[email protected]
[Digital Radio Microphone in Japan]
The Conclusion of Digital Advantages
□ Maximum number of simultaneous operable channel:
10 channels (vs. analogue: 6 channels )
□ Minimum distance to avoid interference:
30m (vs. analogue: 180m )
□ Capable number of interference-free areas :
19 ( vs. Analogue: 7 )
□ Capable number of interference-free areas considering the
placement by frequency interleave :
( vs. Analogue: No )
□ Secured communication :
Yes ( vs. Analogue: No )
□ Remote operation and the other transmitted information:
Possible ( vs. Analogue: Impossible )