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5. Operation
By applying an ACC-513 or ACC-514 to the SD-160, which is intended to be used as a
radio data-generating device utilizing GMSK or FFSK type modulation. There is also a
facility, called Micro-controller Unit, to control your overall application, including the
radio, and to handle data to transmit or receive. The radio is controlled through the DB-
15 connector and interfaces with a DTE by interface cable.
In operation, the radio is placed into the transmit condition by receiving data from DTE.
If the radio receives data, the slave MCU of the ACC-513/514 saves that data in its
memory and automatically creates a PTT signal at the same time to get the RF stage to
prepare for transmission. To avoid data loss in transition time of the RF stage, it is
important that there is a delay between activating the PTT signal and applying the data
to the RF stage. In these processes, there are many tunable parameters, which will be
explained in the next section, to provide maximum performance for user application.
This section describes the basic connection for data transmission or radio control and
then explains important parameters for data transmission.
5.1. Serial interface
In some systems, where data is required to be inputted to a SCADA system or simple
PC logger, the most useful receiver output will be the RS-232 serial stream. Any
system using serial data output will also require DTE(Data Terminal Equipment) such as
a PC, or workstation driver package, or PDA, to display the data and upload it into a
host process. So, To interface with these external equipment, the SD-160 contains a 15
pins D-sub female connector. The serial interface is configured as DCE with the pin out
shown in the table below.
D-Type
Pin No.
Function Description
Signal
Type Input/
Output
1
Data modulation IN
(Tx Mod)
Signal is directly injected to MOD through
data low pass filter without pre-emphasis.
Analog signal
1KHz audio at 60%
peak system deviation
input level =
100 to 120mVrms
I/P
2
Data unfiltered OUT
(RX disc)
Discriminator audio from the SD-160. This is
the unprocessed AF signal prior to tone
filtering and de-emphasis.
Analog signal
1KHz audio at 60%
peak system deviation
produces
200 to 300mVrms
O/P
3 PTT
In
Signal from the ‘external device’ to key the TTL level
I/P