AN4133

An overview of ARIB STD-T108 regulation

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1

An overview of ARIB STD-T108 regulation

Radio equipment defined in this standard utilizes 915 to 930 MHz bandwidth. The ARIB

STD-T108 defines two different types of possible categories of application:

1.

Convenience radio stations

2.

Low-power radio stations

A short description of the two different categories is given in the following sections. The

main difference concerns the output power and band frequency used.

1.1

Convenience radio stations

Devices that operate in convenience radio stations will work in using either a simplex,

duplex, or semi-duplex broadcast method. The contents of communications are primarily the

signals for telemetry, telecontrol and data transmission systems. The operating frequency

band is between 920.5 MHz and 923.5 MHz. The maximum permitted antenna power is

250 mW (+24 dBm on a 50 ohm load, +27 dBm EIRP considering an antenna of 3 dBi gain).

A radio channel consists of up to 5 consecutive unit radio channels which are defined such

that their center frequency is located from 920.6 MHz to 923.4 MHz with 200 kHz separation

and a bandwidth of 200 kHz. There aren't specific requirements for the modulation method,

while the permissible value for occupied bandwidth is (200 x n) kHz or less, where n is the

number of unit radio channels constituting the entire radio channel and is an integer from 1

to 5.

An adjacent channel leakage power is permitted: two different channel masks are defined,

one for systems that work in the 920.5 MHz to 922.3 MHz band and a second one for the

systems that work in the 922.3 to 923.5 MHz band. For the two different masks refer to the

figures 3-1 and 3-2 of the ARIB STD-T108 regulation cited in References on page 33.

For the transmitter a permissible value for unwanted emission intensity is defined (see

Table 1).

For the receiver a limit for the secondary radiated emissions is defined (see Table 2).

Table 1.

Permissible values for unwanted emission intensity

Frequency band

Spurious emission strength (average power)

Reference bandwidth

f <= 710 MHz

-36 dBm

100 kHz

710 MHz < f

≤ 900 MHz

-55 dBm

1 MHz

900 MHz < f

≤ 915 MHz

-55 dBm

100 kHz

915 MHz < f

≤ 920.3 MHz

-36 dBm

100 kHz

920.3 MHz < f

≤ 924.3 MHz

(except for |f-fc|

≤ (200+100xn) kHz)

-55 dBm

100 kHz

924.3 MHz < f

≤ 930 MHz

-36 dBm

100 kHz

930 MHz < f

≤ 1000 MHz

-55 dBm

100 kHz

1000 MHz < f

≤ 1215 MHz

-45 dBm

1 MHz

1215 MHz < f

-30 dBm

1 MHz