DIGITAL TRANSMITTER/RECEIVER 104 (DTR104)
OVERVIEW
 The RT Logic Digital Transmitter/Receiver 104 (DTR104) is a mobile, modular, software-defined communications modem and digital processing unit. It can be configured to support one or more channels of telemetry, commanding, command echo, ranging, and telemetry loopback simulation functions. It also is designed to support mission communications in the field over a KIV-7 crypto interface. External interfaces are 70 MHz IF and baseband (antenna side), Ethernet, and various digital protocols. A PC104 architecture gives it a semi-rugged form factor ready for use in the field.

APPLICATION
 The DTR104 is well suited for in-theater, ground station,and satellite test communications applications. The highly modular and flexible architecture allows the DTR104 to be easily customized for single or multiple stream applications with customer-selected test points and test functions. Digital spectrum analysis functions, as well as In-phase and Quadrature (I/Q) vector diagrams are available to assist in monitoring of input signal characteristics. Internal Bit Error Rate (BER) firmware supports performance measurement with standard external BER testers. All signal processing is performed in software and Field-Programmable Gate Arrays (FPGAs), so new customized processing can easily be added. Control and status interfaces are network-based and come with a platform independent Graphical User Interface (GUI) and Application Program Interface (API). Telemetry and command data interfaces can be configured as direct digital or network-based connections.

The system supports many of the basic processing functions of its sister product, the T400XR. It is recommended when a cost-effective, single function, or extremely compact multichannel product is needed, or when customized processing is required. The system interfaces with RT Logic’s T400FC (Frequency Converter System) product to provide full RF-to-network capability. It also interfaces to the RT Logic T500GT for transfer of data/clock/time, and multistream MUX/DEMUX across a WAN.
FEATURES
Telemetry Acquisition
  • IF Input Frequency: 50 To 90 MHz
  • IF Input Power Level: <-60 dBm To +10 dBm
  • Acquisition Range: ±1 MHz
  • Maximum Doppler Range: <10 kHz/sec
Demodulation
  • Direct PSK (BPSK/QPSK/OQPSK/UAQPSK)
  • Symbol Rates: Up To 20 Msps
  • Subcarrier BPSK/QPSK
  • Subcarrier Frequency: 1 kHz To 20 MHz
  • Viterbi/R-S Decoding: Rate 1/2, CCSDS R-S
  • TDRSS Downlink: Spread Spectrum
I/O
  • Baseband Input/Output
  • RS-422 Dedicated Inputs: 8 Pair
  • RS-422 Dedicated Outputs: 8 Pair
  • RS-422 Selectable I/O: 4 Pair
  • TLL Selectable I/O: 16 Signals
 Command Generator/Modulator
  • SGLS/USB Commanding
  • Output Frequency: 50 MHz To 90 MHz
  • IF Output Level: -40 dBm To -3 dBm
Modulation
  • Direct PSK (BPSK/QPSK/OQPSK/UAQPSK)
  • Two Subcarriers: SGLS/USB
  • Subcarrier Frequency: 1 kHz To 20 MHz
  • Analog Input: FM/PM/AM
  • TDRSS Uplink: Spread Spectrum
Ranging
  • SGLS PRN Ranging
  • USB Tone Ranging
  • TDRSS Ranging
Operating Environment
  • 0 ºC To 50 ºC
  • 10 % To 90% Relative Humidity
ARCHITECTURE
 RT Logic’s Telemetrix® products form reconfigurable systems for satellite ground and test/range applications. The DTR104 is based on RT Logic’s Digital Transmitter Receiver (DTR-70) and Digital Front-end Processor (DFP) PMC modules. An EPIC form factor XE-800 single board computer provides a reconfigurable, digital host platform for the DTR104 IF (70 MHz) and baseband processing functions.

Receiver (DTR-70): An analog section on the DTR-70 filters the IF input that provides Automatic Gain Control (AGC), and generates 12-bit digital samples of the received signal. The Receiver supports Phase-Shift Keying (PSK) and subcarrier demodulation, bit synchronization, Viterbi decoding, and ranging. In addition to the IF input, the DTR-70 accepts baseband input, generates baseband and IF outputs, and has multiple TTL/RS-422 signal lines to support external interfaces. Transmitter (DTR-70): Implements a wide variety of signal modulation schemes. The full Space-Ground Link System (SGLS) and Spacecraft Tracking and Data Acquisition Network (STDN) uplink spectrum is supported, including Frequency-Shift Keying/Amplitude Modulation (FSK/AM) command tones, Phase-Shift Keying (PSK) subcarriers, Pseudo-Random Noise (PRN) ranging, and main Phase Modulation (PM) carrier. The modulator can also be used to generate complex downlink signals for test loops that include telemetry data (main carrier and subcarrier), command, and range tones. Digital Front-end Processing (DFP): Firmware personalities can be hosted to support frame synchronization, bit synchronization, signal multiplex/demultiplex, PCM simulation, Bit Error Rate Test (BERT) functions, command formatting, echo check, and Reed-Solomon encoding and decoding. The DFP provides multiple TTL, RS-422, and LVDS signal lines.