Monday, January 4, 2010

The ClockMite Transceiver

As the name suggests, this design follows the basic ideas of the RockMite transceiver. It will be, however, more digital...
First ideas are the following. The bag of components will be containing the following
  1. one oscillator for 5.0680MHz
  2. one oscillator for 5.0688MHz
  3. RA3AAE mixer for RX
  4. one XOR-doubler for TX
  5. 74HC4066 switch
  6. 12F629 controller
The doubler and the mixer will ensure operating frequencies of 10.1360MHz and 10.1376MHz, which represents a difference of 1.6kHz (surprise surprise). A 1.6kHz tone is not really pleasant to listen to, I agree, but the simplicity of this transceiver will make up for it.

Both oscillators will be on at all times. Both oscillators are routed (74HC4066) to the active doubler which by default is switched off.

TX: The doubler is switched on only when the transmitter is keyed. The controller will route an oscillator to the doubler and activate the same.

RX: One oscillator is routed to the mixer, preferably via a 5.0688 crystal.

The controller will include a iambic keyer but will also allow for straight keying. A further task of the controller is to toggle between the high and low frequencies.

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