2400/19200 bps 4-CH 13/27MHz FSK receiver
3.3V, single conversion, almost discrete design, no decoding, outputs serial bit-stream (40x90mm).
This receiver is the first part of a transmitter/receiver pair to be developed for a simplex underwater data link. The 2400bps/27MHz receiver/transmitter pair will be a legitimate set for remote control purposes of for instance a model submarine. For model submarines, the use of 13MHz often provides an optimal relationship between the size of a submersed antenna outside the fuselage and range. Currently, the design is being verified and optimised using electronic simulation.
The motivation for this project are "End Of Live" announcements from semiconductor manufacturers. This is what happened to the AX5043, the last transceiver IC suitable for 27MHz. In terms of functionality, SDR could be an alternative to the AX5043. However, the difference in price and dimensions is huge. In addition, an SDR contains multiple ICs, each of which is also subject to EOL announcements. In terms of cost and dimensions, a discrete receiver is comparable to SDR. Multiple alternatives are often available for discrete components such as transistors. As a result, EOL is expected to have less impact on the manufacturability of such a receiver.