UHX1-144-5 Datasheet, PDF (3/7 Pages) Radiometrix Ltd – NBFM Multichannel 500mW VHF Transceiver

Figure 3: Provisional UHX1 footprint
Pin Description
Pins Normal mode
Serial mode
Modem
mode
RF
1A
RF Gnd RF ground
2A
RF in/out To the antenna
3A
RF Gnd RF ground
4A
GND
0V
5A
GND
0V
6A
Vcc (TX) 5V regulated supply for TX
User
1
TXD
DC coupled input for TTL/ CMOS logic
NC
2
TXE
Transmit enable.
NC
Low = TX mode
3
GND
0V
4
Vcc
DC supply input (3.1 –15V) for receiver
5
P3
Parallel channel select MSB
Serial read back BUSY
6
P2
Parallel channel select
TBA
MOD TXD
7
P1
Parallel channel select
TBA
MOD RXD
8
P0
Parallel channel select LSB
PGM in
PGM in
9
RSSI
DC level between 0.5V and 2.5V. 60dB dynamic
range
10
RXD
Open collector output of data slicer
NC
11
AF out
500mV p-p audio. DC coupled, approx 0.8V bias
NC
NOTES:
1. No inversion occurs between TXD and RXD. However, AF out is inverted relative to mod in.
2. P0 - P3 (parallel channel selects) and TXE are active LOW and have internal 47K pullups to 3v.
3. Open collector output RXD has a 47K pullup to 3v.
4. The software incorporates a 1200baud dumb modem, compatible with that implemented in
other Radiometrix narrowband units ( i1200 tones and format ). Modem operation is selected by
a serial command.
5. Main serial port (P0-P3) operates at 9600 baud. (Command set is not the same as TR2M, SMX
families). The unit is capable of operating in 'basic' parallel channel select only mode, or in
serial controlled 'expanded' mode.
6. Transmit power can be set by serial command.
7. RSSI, and other status information, can be read back as a digital value. (on P3).
7a. The RSSI is a high impedence output. If a low impedence voltage source (an op-amp output) is
connected to the RSSI out pin then this voltage (0-2.5v) will override the RSSI value during
RSSI 'digital read' operations.
8. If analogue transmit modulation is needed, then connect a series 1uF cap + 500K trimmer (a
multiturn is advised) in the 'baseband TXD' circuit. Adjust trimmer for 90% of peak deviation
(+/- 2.7KHz) at mean input level.
9. The high current (250mA max.) transmitter supply (5v regulated) is fed to a separate connector
10. A version without a RX/TX switch is available. This unit has a 4 pin RF connector (RX, GND,
TX, GND) and is intended for use with external power amplifiers
Radiometrix Ltd
UHX1 Data Sheet (preliminary)
page 3