TIMTER™ Multi-mode Digital Telemetry Transmitter
11
Quasonix, Inc.
CF = 0 (operate clock free)
BR xxx, where xxx = data rate in Mbps, or BR A for automatic data rate
AIR x, where x = 0 for zero DC bias and x = 1 for 1.65V DC bias
1.3.13 Adapter Plate
– AP
Use this option to include the 2.5” x 3.5” adapter plate (hardware accessory) with the order.
1.3.14 Baud Rate Option
– BRx
The BR option changes the serial communications default baud rate on the transmitter to the one selected. A number
from 0-8 follows the BR option request. Corresponding values are as follows: 0 = 57600 (Standard default for all
Quasonix transmitters); 1 = 4800; 2 = 9600; 3 = 19200; 4 = 38400; 5 = 56000; 6 = 57600; 7 = 115200; 8 = 230400.
1.3.15 CP07 Control Protocol Option
– C7
The Quasonix interpretation of IRIG 106-17, Appendix 2-C serial control protocol (CP07), “provides standards for
commands, queries, and status information when communicating with telemetry transmitters configured with
communication ports.” The Basic command set contains the minimum (required) commands for transmitter control,
query, and status. The Extended command set contains optional commands that may or may not be implemented at
the manufacturer’s discretion. CP07 is enabled when the C7 option is requested.
The default baud rate for CP07 transmitters is 9600.
1.3.16 Convolutional Encoder Option
– CE
The CE option enables convolutional encoding and NRZ-M conversion. This encoding adds redundant information
to the transmitted data stream to help detect and correct bit errors that may occur, particularly due to predominantly
Gaussian noise. Use of convolutional encoding requires a matching Viterbi decoder in the receiver to extract the
source data. The encoded data rate will be twice the source data rate, and the occupied bandwidth will also be
doubled.
For example, the transmitter has two encoders, one for in-phase (“I”) data and one for quadrature (“Q”) data. Call
the input symbol stream I0/Q0, I1/Q1, … . Each encoder outputs 2 bits for every input bit, so call the output bit
stream from the first convolutional encoder I0(1), I0(2), I1(1), I1(2), … , and call the output bit stream from the
second convolutional encoder Q0(1), Q0(2), Q1(1), Q1(2), … . Combining the outputs of the two encoders, then,
the output symbol stream is I0(1)/Q0(1), I0(2)/Q0(2), I1(1)/Q1(1), I1(2)/Q1(2), … .
For modes that do not employ Quadrature modulation, such as PCM/FM, Multi-h CPM, and BPSK, only a single
encoder is used.
A single encoder is implemented exactly as described in the “Consultative Committee for Space Data Systems,
Recommendation for Space Data System Standards, TM Synchronization and Channel Coding, CCSDS 131.0-B-1,
Blue Book, September 2003, Section 3.”
A basic convolutional encoder block diagram, as illustrated in CCSDS 131.0-B1, is shown in Figure 3.
