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I have been working on this design for a while now. I had intended that it be a collaborative effort with the CDG. But since the CDG has been in effect dissolved, I am going to post the current effort here until I find a more appropriate forum subject.
Originally, this was intended to be predominately digital processing of the sampled RX signal. But implementing this was beyond the practical capabilities of the available processors. Even an 80MHz PIC32 was borderline for the DSP that had to be accomplished and still leave enough processor reserve to handle the user interface and user feedback that would be needed.
So, the design was reworked to provide analog conditioning of the RX data and the make it available to the uPC for discrimination and deterministic processing. For signal conditioning uPC control is stressed vs. uPC signal processing. The intended design makes use of digital control of RX gain, LP filter control, as well as the documented PI timing.
The design is intended to provide a robust and flexible base with which to offer many options for PI MD operation. It is also intended to make use of Carl's USB P18F4550 board for operation and control.
The current design intention is for it to be made up of 2 boards. One board to be the PS, TX, and RX. The second board would be the 8 channel S&H, ADC, and audio.
I have completed the design of the PS/TX/RX board (Eagle) and am in the process of building the prototype. I have coded the PIC code to generate the TX/RX timing signals. I am currently waiting for an 18F4550 to verify and test the PIC code that is designed to date. I have checked it out using a 18F4431 @ 20MHz (which is to slow to achieve timing requirements) that I have, but I need to verify timing and operation at 48MHz.
The attached zip file contains the document that I have created (to help keep my project somewhat focused), and the PIC code to date.
Comments are welcomed.
Regards,
J. L. King
Originally, this was intended to be predominately digital processing of the sampled RX signal. But implementing this was beyond the practical capabilities of the available processors. Even an 80MHz PIC32 was borderline for the DSP that had to be accomplished and still leave enough processor reserve to handle the user interface and user feedback that would be needed.
So, the design was reworked to provide analog conditioning of the RX data and the make it available to the uPC for discrimination and deterministic processing. For signal conditioning uPC control is stressed vs. uPC signal processing. The intended design makes use of digital control of RX gain, LP filter control, as well as the documented PI timing.
The design is intended to provide a robust and flexible base with which to offer many options for PI MD operation. It is also intended to make use of Carl's USB P18F4550 board for operation and control.
The current design intention is for it to be made up of 2 boards. One board to be the PS, TX, and RX. The second board would be the 8 channel S&H, ADC, and audio.
I have completed the design of the PS/TX/RX board (Eagle) and am in the process of building the prototype. I have coded the PIC code to generate the TX/RX timing signals. I am currently waiting for an 18F4550 to verify and test the PIC code that is designed to date. I have checked it out using a 18F4431 @ 20MHz (which is to slow to achieve timing requirements) that I have, but I need to verify timing and operation at 48MHz.
The attached zip file contains the document that I have created (to help keep my project somewhat focused), and the PIC code to date.
Comments are welcomed.
Regards,
J. L. King
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