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MODULE DESCRIPTION

The RM Series is a SAW-(Surface Acoustic Wave) based transmitter designed

to be utilized in combination with a matching RM Series receiver. By adding a

simple antenna, the pair can transfer serial data at distances well in excess

of 500 feet. The range of the RF link is widely variable and depends upon

many factors including the type of antenna employed and the operating

environment. The 500 ft. quoted range is a conservative operating distance

over open ground using 1/4-whip antennae at both ends of the link at 5 feet

above the ground. Use of a less efficient antenna or adverse environmental

factors such as interference, obstacles, or multipath can substantially reduce

the link’s reliable working range. Slowing the data rate or utilizing a directional

antenna (especially on the receiver) can provide increased performance but

may not comply with licensing requirements. It is recommended that your

individual application be reviewed with Linx prior to entering production or

seeking approvals.

figure 1: LINX-TX block diagram

THE SAW BASED DESIGN ADVANTAGE

The SAW (Surface Acoustic Wave) device provides a highly accurate

frequency source with excellent immunity to frequency shift due to age or

temperature. By using a SAW to insure accurate frequency control on the

transmitter module the receiver’s pass opening can be quite narrow, resulting

in outstanding sensitivity and greater immunity to interfering signals. In order

to frequency modulate this carrier the SAW is externally pulled to obtain the

necessary deviation.

By employing a SAW on both the RM transmitter and receiver the units provide

an excellent performance rivaling far more complex and costly systems. The

SAW device, in combination with advanced design and manufacturing

techniques, has made it possible to dramatically reduce the size and cost of

an RF link while enhancing its performance. The end user benefits from

improved product range and reliability and the OEM manufacturer from lower

cost and simpler manufacturing procedures.