Modem vhf
1017 palavras
5 páginas
TC4:V/UHF Modem Module
Waveforms
[Prelim.]
High Data Rate Modem
The TC4 is a very compact high-performance V/UHF high data rate (HDR) modem module. The module is intended for integration into V/UHF radios and systems with an audio bandwidth exceeding 21 kHz (-30 db). Data is transferred at rates of up to 96,000 bps over a standard 25 kHz (-50 dB) V/UHF radio channel.
The TC4 offers a choice of two waveforms: • • RM-VH1: Optimized for naval channels RM-VH2: Optimized for land mobile channels
TC4-HDR supports following modem data rates:
DATA R ATE 96000 76800 64000 48000 32000 16000 MODULATION 128-QAM* 64-QAM 32-QAM 16-QAM 3π/8 8-PSK π/4 QPSK
CODE RATE
SNR FOR BER< 10-5 27 23 18 14 10 4
0.86 0.80 0.80 0.75 0.67 0.50
* This data rate requires an end-user certificate. The interleaver settings are shown in the table below.
# 1 2 DATA RATE 96000 76800 64000 48000 32000 16000 USER DATA PAYLOAD [BYTES] US 20 MS 240 192 160 120 80 40 S 160 MS 1920 1536 1280 960 640 320 L 2560 MS 30720 24576 20480 15360 10240 5120
Key Features & Benefits
• • • • • • • • • • High Data Rate Modem 96000 bps (coded) in a 25 kHz VHF or UHF channel Embedded ARQ Interface for external ARQ (e.g. S 5066) Collision Avoidance Capability Analog or digital audio interface Low power consumption (< 1.3 W) Compact size: 33 x 55 x 8 mm RAP1/RIPC Control Protocol Easy system integration
3 4 5 6
Embedded ARQ
The TC4 offers the optional use of an internal ARQ protocol which ensures error-free delivery of data. This has advantages including following: • Wide SNR range and V/UHF channel conditions • No error-amplification due to crypto
MOD. 64-QAM 8-PSK PACKET [BYTES] 377 313 THROUGHPUT* [BPS] 63,495 26,358 EFFICIENCY
ARQ MODE V-25-Q64-H4 V-25-Q8-H2
82.68% 82.37%
* Max data rate excluding link setup (LSU).
Low data rates (up to 32 kbps) use Offset QPSK and 8-PSK waveforms. The low data rates are suitable for radios with a non-linear power amplifier (PA). The