TSAT 3000 - Telemetry and data transfer via SATellite
TSAT 3000 Configuration Parameter Description, January 2013 Page 91 of 124
3.11.24 PHL_TX_FREQUENCY_ADJUST
Default 0, Range –10000…+10000
When operating in 2150-Compatibility mode (bit 10 – 0x0400 in UTL_UTILITY_MASK), the
inbound carrier from RTs with different hardware revisions (TSAT 2100, 2150 and 3000), and
different DSP software versions (
2100 DSP <= 22.4.0 – 2100/50 DSP >= 22.5.0 – 3000 DSP) are
received at the HUB at slightly different frequencies. Up to 150 Hz difference has been observed.
This doesn’t cause any problem in homogeneos network with only TSAT 2100, TSAT 2150 or
TSAT 3000. However, in a network with both older and newer hardware and/or DSP software, the
RTs will send at different frequencies, and the HUB will have problem to receive all RTs.
Therfore, we have to slightly adjust the RT’s transmitting frequency.
Ver <= 30.8.0
Not Implemented.
Ver >= 31.0.0
HUB: It’s possible to adjust the HUB’s outbound frequency, but why should you do this?
RT:
PHL_TX_FREQUENCY_ADJUST [Hz] is used to adjust the RT’s inbound frequency.
Note: CCU ver <= 31.8.0 will restart DSP 10 seconds after CURRENT value is changed, when
this option is enabled by bit 2 (0x0004) in
UTL_UTILITY_MASK.
CCU Ver >= 31.8.1 (R4.7.1) will not
restart DSP, because PHL_TX_FREQUENCY_ADJUST is
changed immediately in DSP Ver >= 3.2.2.
HUB Ver >= 31.1.0
When HUB operate in 2150-Compatibility mode, the Automatic Frequency Adjustment (AFA)
mechanism will adjust the frequency of all TSAT 2100/50 RTs with DSP version >= P22.5.0
(provided option is enabled in RT by bit 23 (0x80.0000) in
UTL_UTILITY_MASK).
Assuming all TSAT 2100/50 RTs are version >= 25.0.0 (and all 3000 RTs >= 31.0.0), AFA
works as follow:
• The RT’s DSP version and HW revision is signaled from RT to HUB in all
POLL_ACK
packets.
• The HUB will select one of the RTs as reference frequency, and keep this RT as
Reference-RT until link has been reported DOWN (for more than 10 poll-cycles), or a more
prioritized RT is reported UP (i.e. is included in the poll-cycle for more than 10 poll-cycles).
The HUB is selecting the Reference-RT after the following criteria:
1) Preferable the first
TSAT 3000, or 2100 RT with DSP version <= P22.4.0, in poll-cycle is
selected, because such RTs cannot adjust frequency.
2) The first
TSAT 2100 RT in poll-cycle.
3) The first
RT in poll-cycle.
• The frequency adjustment (+/–1 or 2 Hz compared to the Reference-RT) is signaled to each
of the RTs (but not the Reference-RT) in
SYNC packets. Only TSAT 2100/50 RTs with DSP
version >= P22.5.0 are requested to modify their TX frequency.
• Only TSAT 2100/50 RTs with AFA enabled, will actually adjust their TX frequency. The
CURRENT value of PHL_TX_FREQUENCY_ADJUST will be modified (+/–1 or 2 Hz).
However, it cannot be automatically adjusted to a value outside the range (
EEPROM value
of
PHL_TX_FREQUENCY_ADJUST) +/–150 Hz.
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