Park Air Systems T6TR, User Documentation

Page: 22 / 136

T6TR VHF 50 W Transceiver Page 12 Specification
Back to Transceiver
Main Page
Mode 3
Mode 3 parameters are identical to AM-Voice mode with the following exceptions.
Transmit RF Characteristics
RF power Rise Time
The transceiver produces more than 90% of full power output within the first 2 symbols of the power
stabilization segment, which is the first segment of the training sequence and consists of 4 symbols each
representing 000.
RF Power Decay Time
The output power decays by more than 20 dB within 2.5 symbols of the middle of the final symbol.
Channel Spacing
25 kHz channel spacing only.
Transmit Modulation Characteristics
Mode
Mode 3 uses Time Division Multiple Access (TDMA) differentially encoded 8-phase shift keying (D8PSK),
using a raised cosine filter with
α
=0.6 (nominal value), emission designator 14K0G7WET. Information is
differentially encoded with 3 bits per symbol transmitted as changes in phase rather than absolute phase.
The data stream is divided into groups of 3 consecutive data bits, least significant bit first. Zeros are
padded to the end of transmissions if needed for the final channel symbol.
Modulation Rate
The symbol rate is 10,500 symbols/second (±0.005%), resulting in a nominal bit rate of 31,500 bits/s.
RMS Phase Error
The RMS phase error is less than 3°. The error vector magnitude is less than 6%.
Phase Acceleration
The total frequency change during the transmission of the unique word is less than 10 Hz. After this, the
phase acceleration is less than 500 Hz/s.
Receive RF Characteristics
Sensitivity
The transceiver has a sensitivity better than -102 dBm for 1x10
-3
Bit Error Rate (BER) with Reed
Solomon decoding off.
In order to improve co-location performance where maximum sensitivity cannot be realized due to large
unwanted signals, the transceiver’s sensitivity can be reduced by 6 dB. This is achieved by switching on
the 6 dB RF pre-attenuator from the front panel menu system.