Quasonix TIMTER Installation And Operation Manual page 18

TIMTER™ Multi-mode Dual
Telemetry Transmitter
Figure 2: CCSDS 131.0-B-1 Rendering of Basic Convolutional Encoder Diagram
1.3.16 Clock-free Baseband Interface Option – CF
Clock-free is an optional mode that transmits user data, but uses an internal bit sync to take the place of the normal
external clock. The standard TIMTER requires external clock and data inputs. With the CF option, no external clock
is required. The clock is generated directly from the data and a user-specified bit rate.
Because the internal bit sync's clock takes the place of the normal external clock in clock-free mode, the selected
clock source must be external for clock-free just like it is for normal clock/data. This mode is most often used to
retrofit older analog transmitters in TM systems where the crypto device does not deliver a clock to the transmitter.
The commanded clock-free rate can be saved using the SV command, and if so, it will be restored at power-on.
When the CF option is used, the bit rate range is 0.1 to 35 Mbps for all waveform modes. It is limited by the bit rate
achievable for the current mode. (Refer also to the HR and LR options for extended bit rates, and the ID option for
Internal Clock and Data.)
Do not confuse the CF option with the CS command.
Internal clock (CS 1 Command) is used when the transmitter is to be a test source only. The unit transmits the
selected internal data pattern at the bit rate set by the user via the IC command. The internal clock is not used to
transmit actual payload data.
External clock (CS 0 Command) is the normal mode: the user supplies clock and data, or in clock-free mode, the
user provides only valid data. Refer to Table 12 for user commands.
10 Quasonix, Inc.