PL | EN
FIG. 1
Superheterodyne receiver with two IF frequencies. The first IF is about 21 MHz and the second IF is the standard 455 kHz. (This filter is removed). This receiver based on the MC3367 integrated circuit from MOTOROLA.
FIG. 2
An antenna, an RF preamplifier and a DC-switch for an IC.
FIG. 3
Other conception of an RF unit. Due to the self reception, the antenna is as far as possible from the local oscillator. This receiver based on the SL6609 direct conversion FSK data receiver from GEC PLESSEY.
FIG. 4
A front view. An RF preamp., an IC and the local oscillator.
FIG.1
Control unit with two uC on the PCB. As far as I remember, the first was for acquiring & decoding, the second one for other logic - buttons, an vibrating motor, a buzzer and a micro incandescent lamp. In this particular PCB uControllers are removed. At the bottom right is a DC-DC converter. This project was beep only pager - the Beeper. We implemented the ST6220 microcontrollers from SGS-THOMSON.
FIG. 2
Remaining components - on the left you see two large capacitors mounted underneath the DC-DC converter. this was the only way to suppress the noise from this converter. The RF part -on the separate board, table 1/fig. 1&2 - was mounted at this side. This PCB side was designed to have a large ground area; remaining tracks are DC-only.
FIG. 1
Evaluation board for PCF8866 IC LCD controller and a LCD itself. The above PCB is a evaluation board for alphanumeric/beep pager. The one 7-segment from 8 characters LCD mimics an letter. The PCF8866 come from PHILIPS.
FIG. 2
Completed LC display and an controller - HD66702 from Hitachi. It was probably the first ever commercial available 5x7 and 5x10 dot matrix liquid crystal display controller and driver - January 1992. We received a sample from Japan. It was assembled by hand.
FIG. 3
Bottom side
PHILIPS is a registered trademark of Royal Philips Electronics N.V.
ITACHI is a registered trademark of Hitachi, Ltd.