H-Mode Mixer V1
1. Introduction
This is my first attempt at packaging a version of the H-Mode mixer developed by Colin Horabin G3SBI and revised by Giancarlo Moda I7SWX. I have taken the revised circuit which has one less RF transformer and constructed it in a self contained module that may be built and tested and then mounted onto a printed circuit.
The following photographs shows its construction.
Side 1
Local oscillator input on the left, RF signal input on the right. The IC is a low voltage line receiver used as a squarer to drive the mixer.
Side 2
IF output on the right. The IC is the FST3125 bus switch mixer.
The module is constructed with three layers using double sided 1.6mm and single sided 0.8mm PCB. The inner layer being an almost continuous groundplane and also the negative (0v) rail. The wires will eventually be used to connect to the motherboard. A 3.6V DC supply is required.
This version is a little cramped around the RF transformer on the right hand side of side 2 so a new layout will be drawn when all measurements on this first prototype are completed and any other errors resolved. I will also be packaging an alternative three transformer version using the FST3257 and 74AC04 based squarer in the near future.
The original mixer design may be found at: CDG2000 Transceiver.htm
A complete, updated, high performance front end by Martein PA3AKE and based on the H-Mode mixer may be found here.
