CIRCUIT DESIGN CDP-RX-03AS Manuel d'utilisation - Page 5
Parcourez en ligne ou téléchargez le pdf Manuel d'utilisation pour {nom_de_la_catégorie} CIRCUIT DESIGN CDP-RX-03AS. CIRCUIT DESIGN CDP-RX-03AS 10 pages. Uhf fm-narrow band radio data receiver
Imprimer la pagefilter and comparator. For simple FSK modulation of digital data, the DATA out terminal can
be used. The signal can be easily connected to other digital circuits.
The receiver has no internal mute circuit to avoid delays and achieve maximum sensitivity.
The AF and DATA output will show noise on the output when no signal is received. Valid data
signals can be detected by utilizing the RSSI output.
The third output is called RSSI. It is an indicator of the received signal strength. It can be used
to drive an external mute circuit.
Control terminal can be used to control Vcc supply for internal circuit.
Antennas:
Most important for effective data transmission is selection of a good antenna, and RF
grounding, both for the transmitter and the receiver. Without an antenna it is impossible to
transmit data over a long distance range.
The receiver has a simple antenna input pin. Any suitable UHF antenna can be connected to it.
The easiest way to connect an antenna to the CDP-RX-03AS is to solder an 8.6cm (868MHz)
or 17.3cm (434MHz) wire directly to the antenna input. If the receiving antenna is installed
away from the receiver module, a 50-Ohm Coax antenna wire can be used. The shielding of
the antenna wire should be soldered to the case near the antenna input of the CDP-RX-03AS.
It is possible, but not recommended to connect the receiver module and the antenna by a
connection on a PCB. This will decrease the receiver performance in most cases.
In most cases the following basic rules will help you.
• Connect an antenna with 50-Ohm impedance.
• Lambda/4 whip antenna length is approximately 17.3cm for 434MHz and 8.6cm for
868Mhz.
• Place the antenna vertically, straight up or down from the transmitter and receiver module.
• Do not cover the antenna with metal parts.
• The connection of the metal surface of the transmitter case to a larger metal part (ground
plane) will increase radiation efficiency. Such metal part should not be placed near the
antenna.
• The human body can have similar effects like metal objects. Pocket transmitters should be
taken in the hand and put in a position away from the body and pointed in the direction of
the receiver.
• Best range is achieved if the transmitter and receiver antenna have a direct visual
connection. Any object in between the transmitter and receiver antenna, and metallic
objects in particular, will decrease the range.
• The transmission is influenced by reflections of the transmitter signal on metallic surfaces
and building. There is possibility to have data error by overlaying the direct and reflected
signal.
CDP-RX-03AS UHF Radio Data Module Operation Guide
CIRCUIT DESIGN, INC.
5