DS600-10 March ‘06

©2004 Reg. No. 227 4001, ENGLAND

Page 19

RF / IR Encoder / Decoder Chipset

RF Evaluation Boards,

RF600E

RF600D

HiRK decoder area.

AM-HiRK-433 receiver/decoder module. (M5)

Learn switch.

(SW2)

Learn LED.

(LED7)

Data LED’s.

(LED8, 9, 10)

Power supply area.

5 volt regulator.

(U5)

Supply indicator

(LED11)

The radio keyfob is a standard R. F. Solutions AM-110C3-433 keyfob which contains an RF600E encoder

chip and also an AM radio transmitter circuit. Three push buttons allow the user to send commands to the

RFEVAL2 board where the signals will be received and decoded.

The RFEVAL2 board is supplied with a circuit diagram and also a parts list and can be used for a wide

range of development tasks including the following.

Remote switching - software and hardware systems can be simply prototyped and tested.

Range and environment testing - these initial stages of project design can be carried out and valuable

results obtained without the expense of PCB design and procurement.

Solve the great AM/FM question - the low cost of AM modules must be balanced with their lower

performance when compared to FM and accurate comparisons of performance can be carried out with this

board.

Aerial test - the transmitter board has provision for both AM and FM modules and can be fitted with helical

stub and 1/4 wave whip aerials, thus allowing module and aerial performance to be tested and optimised.

RF Input Circuit.

The RF input stage of the RFEVAL2 board can be implemented using either a radio receiver module or

alternately using the composite hybrid receiver / decoder HiRK module.

The can accept up to 3 radio modules and each module has an associated pair of option links. One of

these couples the +5 volt supply to the module and the other allows for the connection of the ‘data out’

signal to the decoder IC. The need for a +5 volt option link may not be immediately apparent but most radio

receivers are in practice transmitters as well and radiate from their local oscillator stage. If these signals

are picked up by a nearby receiver then they may well cause distortion of incoming ‘real’ signals or in

extreme cases my completely prevent operation of the receiver. The four modules which may be fitted to

the board are as follows.

FM-RRFQ1 FM module (M3) which receives signals from a compatible FM transmitter module such as the

FM-RTFQ1. Operation is possible at data rates up to 4.8Kbps and at distances up to 250 metres over open

ground.

AM-HRR3 AM module (M4) which receives signals from a compatible AM transmitter module such as the

AM-RT4 or AM-RT5. These modules will operate at up to 4 Kbps and over a range of up to 500 metres.

The super-regenerative circuit used, results in a low cost device with adequate performance for many short

range applications. Note that this module position will accept RRS3 modules which utilise a superhet circuit

to give improved performance and range over the HRR3 devices.

Irrespective of how many modules are fitted, it will be necessary to connect the +5 volt and data lines of

one module using the link options filed on the PCB. It is important that only one pair of links be made at any

one time to prevent inter-module interference and also to prevent damage to the ‘data out’ signal pins on

the modules. The following table gives the link option fitment for each module.