Multiplexer Module (TX2A/TX4A)
18 November 1996
MUX-8
All multiplexed antennas have one common terminal, which is the antenna terminal ANT. The
other antenna terminals are connected to ground GNDTX via a switch. The characteristics of the
TX/RX antennas are shown in figure 3.
Figure 3: Configuration of TIRIS Standard TX/RX Antennas
For more details refer to Section 4 “Installation and Use of the 4 Channel Multiplexer”.
The active TX/RX channel is selected by the two binary weighted channel select signals CSA and
CSB, table 5 shows the binary configuration needed to select each channel. The configuration of
the input signals CSA and CSB and the Enable signal (ENTX-) is shown in figure 4.
Figure 4: Configuration for Input Signals CSA, CSB and Enable
The Multiplexer has built-in voltage regulators to supply the logic part and the MOS FET drivers
with regulated voltage.
The input supply voltage must be connected to the pins V_IN and GND of connector J1. The input
voltage needs to be stabilized (i.e. DC), but not regulated and can be between 10 and 24 V.
Note:
The Multiplexer must not be supplied by Switched Mode Power Supplies (SMPS). This
is because most SMPS operate at frequencies around 50 kHz. The harmonics of the
generated field can interfere with the TIRIS receiver. Therefore only use linear power
supplies, or SMPS with a fundamental operating frequency of 200 kHz or higher.
Figure 5 shows how the Multiplexer should be connected to the Power RFM and how the TX/RX
antennas should be connected. Figure 6 shows how the Multiplexer should be connected to the
S25x0 Reader, how the TX/RX antennas and how the power should be connected.
