nanoTX
TM
Telemetry Transmitter
57
Quasonix, Inc.
4.2.1.1
Additional Command Set Details
4.2.1.1.1 Internal Clock Rate
– IC
This rate is used if the clock source is set to internal (CS 1). It should not be confused with “BR”, which sets the rate
of the internal bit sync, which phase locks to the externally applied data, if Clock-free is enabled.
If no argument is passed, the unit reports the clock frequency. If a valid frequency is given, the internal clock
frequency is set. The frequency is in MHz.
The units used to describe the internal bit rate are sometimes used interchangeably, and may cause confusion.
Megahertz (MHz) and Hertz (Hz) are cycles per second units, while Mbps (megabits per second) and bps (bits per
second) are data rate units.
The internal clock is referred to as “clock,” so Hz or MHz is often used as the unit, since “clock” is a frequency.
If the clock is used to “clock” the bits at X MHz, then the throughput in bits is X Mbps. In other words, the internal
clock also sets the baseband bitrate. That is why, in this case, units of Hz are equated with units of bps.
For example, 5,000,000 Hz or bps may be rewritten as 5.000 MHz or 5.000 Mbps.
4.2.1.1.2 Input Source Selection Command - IS
The IS command is used to select the clock and data source (and the user pattern and clock rate where applicable)
for the transmitter with one command. This command can conceivably replace CS, DS, ID, IC, BR, BT, AIR, CF,
and EN.
This command is standard on all units version 2.409 or greater.
Syntax: IS [ds/?/pnxx/XXXX [cs/AUTO/rate]]
where
ds
is data source which can be:
ET - external TTL data
(if QSX-VxT or -VR enabled)
ER - external RS422 data
(if QSX-VxR or -VR enabled)
EL - external LVDS data
(if QSX-VxL or -VR enabled)
I - internal with currently selected data pattern
PNxx - internal with specified PN sequence
XXXX - internal with specified fixed 4 digit hex pattern
AB - auxilliary input bipolar data
(if -CF and -AI enabled)
AT - auxilliary input TTL data
(if -CF and -AI enabled)
EN - Ethernet
(if -EN enabled)
If ds = ET, then cs MAY be:
•
Nothing (defaults to ET for an external ttl clock)
•
ET for an external TTL clock
Actions:
ds 0, cs 0, bt 1 (if needed), cf 1 (if needed)
•
X for clock free with current BR (if -CF enabled)
Actions:
ds 0, cs 0, (bt 1 if needed), cf 0
•
AUTO for clock free with BR = auto