Part 2 Of A Digital VFO For The G6LBQ Irwell HF Transceiver

For part 1 of the Digital VFO click here.

Digital VFO & RF Oscillator Module

"For The G6LBQ Irwell HF Transceiver"

Welcome to part 2 of my blog post series in which I present further details of my Digital VFO and RF oscillator module for the “Irwell HF Transceiver project”. This is a significant building block as it will be solely responsible for frequency generation and the control of other modules in the project.

Since I posted part 1 on the blog I have made good progress with the software changes that I outlined. I have added additional commands to JA2GQP’s source code for the I2C Multiplexer and I am now at the stage where I can communicate with two SI5351 devices to produce two chip independent clock signals. In order to achieve this, I have had to make changes to both the main code as well as the SI5351 library file.

For now, I only need to generate two clock signals for my transceiver, one for the VFO and the other for the BFO, this will permit the radio to run as a single conversion superhet in its current state. Once further modules are developed the receiver will be upgraded to a dual conversion superhet which will require a third clock signal for the  conversion oscillator.

The additional software code required to support a third SI5351 is going to be a bit more difficult for me to implement, I hope to replicate JA2GQP’s BFO oscillator code parts for this as it includes a routine for calibrating the BFO frequency and saving it to memory and If I can do this it should pave the way for implementing an IF shift control.

Part 1 Of A Digital VFO For The G6LBQ Irwell HF Transceiver

 Digital VFO & RF Oscillator Module

"For The G6LBQ Irwell HF Transceiver"

In this blog post I present my digital VFO and RF Oscillator module for the Irwell HF Transceiver project which is based around the Silicon Labs CMOS SI5351 Clock Generator.

Before we begin I would like to pay homage to an era in my life which has flourished, brought great happiness, prosperity and achievement. 

I make the aforementioned statement with a sense of humbleness and I also feel privileged to have experienced great wealth in the recent flourishing times. 

If all this has got you thinking I have won the national lottery or been a beneficiary to a nice windfall you are excused and forgiven :)  Truth is I have only ever been good at making other people wealthy and said people choose to forget what the catalyst was to there wealth status!

I digress a little as I sailed off course for a moment there but suffice to say I am very happy with my modest lifestyle.