hopping declaration

FCC ID: TBQT35-915

Attestation Statements

Download: PDF

FCCID_1258676

PORTMAN ELECTRONICS (DONGGUAN) CO., LTD.
NO#10 , Luyi 2 Road, Keyuancheng, Tangxia Town ,Dongguan,China 523718

1. Transmitted modulation:
The product: T35 two way transmitter (FCC ID: TBQT35-915 ) uses the Semtech
SX1211 as the RF Transceiver chipset. The SX1211 transmits at a bit rare of
20 kbps bitrate with 50 kHz frequency deviation, when using the default
12.8MHz crystal of the SM1211 reference design.

2. Hopping frequency assignments:
25 radio channels are used with a constant spacing of 350 kHz between
carrier/center frequencies. The lowest frequency is centered at 910MHz, and the
highest at 918.4 MHz. The random ordering of channels is obtained from
http://random.org/sequences/ using a min and max of 0 and 25

3. Compliance description of hopping Algorithm:
The following describes equal frequency usage, and how the hopping algorithm
occupies each radio channel for less than 400ms in a 20 second period, using 25
hopping channels.
- Slaves nodes in the system liten for synchronization messages from the
master when the slaves are not previously synchronized. Once a slave
has received the master synchronization message, it tracks the channels
used by the master with identical timing. Slaves do not transmit until
requested to by the master. Both Slaves and master are programmed
with identical hopping frequency tables.
- In synchronization mode, the master node sweeps 25 hopping channels at
a rate of 2 milliseconds per channel. The transmitted message (occupancy)
on each channel takes 65~75 milliseconds. The total time spent in
synchronization mode is 750ms for 25 hopping messages and on
SYNC_END notification.

- In dialog mode, the master hops at a rate of 750 milliseconds. On each
radio channel, each of the four slaves is contacted.

- Or, if any of the four nodes fail to response, the system will re-enter
synchronization mode for one sweep of all the channels with sync
messages. The master cycles into synchronization mode every 2.54
second, with approx 2.13 seconds in dialog mode, and the other 0.4
seconds in the synchronization mode. Dialog mode hops five times
between each synchronization mode, four attempts to contact each node
and one notification that synchronization mode will begin.

4. Lab results of compliance test:
These tests were performed on nodes operating at a 20,000bps bitrate from
12.8MHz crystal on the SX1211.

Document Created: 2010-03-30 16:42:40
Document Modified: 2010-03-30 16:42:40

© 2024 FCC.report
This site is not affiliated with or endorsed by the FCC