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figure 1: Overall 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. The

use of a SAW device on both the transmitter and receiver modules allows the

receiver’s pass opening to be quite narrow, resulting in outstanding sensitivity

and greater immunity to interfering signals. As an additional benefit, the SAW

device is manufactured to resonate at a precise frequency, thus eliminating

production tuning and lowering parts count.The SAW device, in combination with

advanced design and manufacturing techniques, has made it possible to reduce

the size and cost of an RF link, while enhancing its performance to a level rivaling

far more complex and costly systems. The end user benefits from improved

product range and reliability and the OEM manufacturer from lower cost and

simpler manufacturing procedures.

MODULE DESCRIPTION

The RM Series is a SAW-(Surface Acoustic Wave) based double-conversion FM

superheterodyne receiver designed to be utilized in combination with a matching

RM Series transmitter. The receiver utilizes a data slicer that is driven by the AF

output. A carrier detect signal is available to indicate to external circuits that a

signal is present. This signal is extremely useful when implementing duty-cycle

power-save circuits or to indicate to external logic that a signal is being received.

It is internally derived from the degree of noise quieting due to the presence of a

receive carrier. By adding a simple antenna, the pair can transfer serial data at

distances well in excess of 500 feet.The range of any 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 typical 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.