Pseudorandom Frequency Hopping Sequence

FCC ID: T2C-CPW90-BT

Attestation Statements

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FCCID_4371903

YEALINK (XIAMEN) NETWORK TECHNOLOGY CO.,LTD WWW.YEALINK.COM Date: 07/19/2019 Federal Communications Commission 7435 Oakland Mills Road Columbia, MD 21046 Statement FCC ID: T2C-CPW90-BT This device uses Bluetooth radio which operates in 2400-2483.5 MHz band, and complies with FCC part 15.247 rules. Bluetooth uses a radio technology called frequency-hopping spread spectrum, which chops up the data being sent and transmits chunks of it on up to 79 bands (1 MHz each; centred from 2402 to 2480 MHz) in the range 2,400-2,483.5 MHz. The transmitter switches hop frequencies 1,600 times per second to assure a high degree of data security. All Bluetooth devices participating in a given piconet are synchronized to the frequency-hopping channel for the piconet. The frequency hopping sequence is determined by the master's device address and the phase of the hopping sequence (the frequency to hop at a specific time) is determined by the master's internal clock. Therefore, all slaves in a piconet must know the master's device address and must synchronize their clocks with the master's clock. Adaptive Frequency Hopping (AFH) was introduced in the Bluetooth specification to provide an effective way for a Bluetooth radio to counteract normal interference. AFH identifies "bad" channels, where either other wireless devices are interfering with the Bluetooth signal or the Bluetooth signal is interfering with another device. The AFH-enabled Bluetooth device will then communicate with other devices within its piconet to share details of any identified bad channels. The devices will then switch to alternative available "good" channels, away from the areas of interference, thus having no impact on the bandwidth used. This device used a random function to mix the channels and produce the pseudo-random lookup-table. This lookup-table is stored in the devices. The devices iterate through this lookup table which results in the pseudo-random channel selection. EUT Pseudorandom Frequency Hopping Sequence Table as below: Channel: 08, 24, 40, 56, 40, 56, 72, 09, 01, 09, 33, 41, 33, 41, 65, 73, 53, 69, 06, 22, 04, 20, 36, 52, 38, 46, 70, 78, 68, 76, 21, 29, 10, 26, 42, 58, 44, 60, 76, 13, 03, 11, 35, 43, 37, 45, 69, 77, 55, 71, 08, 24, 08, 24, 40, 56, 40, 48, 72, 01, 72, 01, 25, 33, 12, 28, 44, 60, 42, 58, 74, 11, 05, 13, 37, 45 etc. The device receiver has input bandwidths that match the hopping channel bandwidths of their corresponding transmitters and shift frequencies in synchronization with the transmitted signals. Signature Stone Lu / Vice General Manager Addr: 309, 3rd Floor, No.16, Yun Ding North Road, Huli Tel: +86-592-5702000 District, Xiamen City, Fujian, P.R. China Fax: +86-592-5702455


Document Created: 2019-07-22 09:15:30
Document Modified: 2019-07-22 09:15:30
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