Meinberg TCR170PEX - Manual (Page 10)

10
Features TCR170PEX
The board TCR170PEX is designed as a standard height board for computers with
PCI Express interface. The data transfer to the computer is done by using a single PCI
Express Lane (x1 board). TCR170PEX serves to decode and generate modulated
(AM) and unmodulated (DC Level Shift) IRIG and AFNOR time codes. AM-codes
are transmitted by modulating the amplitude of a sine wave carrier, unmodulated
codes by variation of the width of pulses.
As standard the module TCR170PEX is equipped with a TCXO (Temperature
Compensated Xtal Oscillator) as master oscillator to provide a high accuracy in
holdover mode of +/- 1 * 10E-8. Optionally an OCXO (Oven Controlled Xtal
Oscillator) is available for better accuracy.
Receiver:
Automatic gain control within the receive circuit for unmodulated codes allows
decoding of IRIG or AFNOR signals with a carrier amplitude of 600 mV
pp
to 8 V
pp
.
The input stage is electrically insulated and has an impedance of either 50
Ω, 600 Ω
or 5 k
Ω, selectable by a jumper. The unmodulated input is accessible via a BNC-
connector in the bracket of TCR170PEX.
Unmodulated or ‘DC Level Shift’ time codes must be connected to the D-Sub-plug
of the module. The receive circuit is insulated by an onboard photocoupler which can
be driven by TTL or RS-422 signals for example. In delivery state of TCR170PEX the
contacts of the D-Sub-plug are not connected to the photocoupler. Two DIP-switches
must be set to the ‘ON’ position for making this connection.
Generator:
The generator of TCR170PEX is capable of producing time codes in IRIG-B or
AFNOR format. They are available as modulated (3 V
pp
/1 V
pp
into 50
Ω) and
unmodulated (DC Level Shift) signals (TTL into 50
Ω and RS-422). A jumper on the
board allows selection of active-high or active-low time codes.
Regarding time code and its offset to UTC, the receiver and the generator can be
configured independantly. Thus TCR170PEX can be used for code conversion.
As an option the module can be delivered with optical inputs/outputs instead of the
modulated signal paths.
The board TCR170PEX provides two configurable serial interfaces (RS-232).
COM0 is available via the Sub-D connector, COM1 can be found at a contact strip of
the board. Two programmable pulse outputs can be connected to the D-Sub-plug by
setting DIP-switches into the ‘ON’ position.
A contact strip on the board provides two TTL inputs (CAP0 and CAP1) that can be
used to capture asynchronous time events. These time stamps are readable via the
PCI-bus or the serial interface and can be evaluated by user software.