Suggestions for digitizer design

[curious_77]

I am interested in designing a high speed digitizer (250 msps, 10-12 bits).
I want to be able to put my design on a small PCB that I can attach to a bigger test board. Due to various reasons, I am unable to use boards from NI or Textronics. From my research so far, the board will have a high speed ADC and most probably a FPGA to store data and transmit it serially to a PC. I have some questions for you guys

1. For a novice designer, is the circuit design and layout going to be hard?

2. I consider the FPGA to be my biggest hurdle. Can you suggest a good FPGA kit that I can practice on?

 

[KlausST]

Hi,

1. For a novice designer, is the circuit design and layout going to be hard?

Definitely YES! If you mean 250 Mega samles per second (or do you mean 250 millisamples per second?)

I don´t think it is a good idea for a novice designer. It´s actually a challenge for an experienced designer..


I´d expect problems with:
* analog input circuit for that high frequency
* FPGA design for that high data throughput
* board layout

Klaus

 

[curious_77]

Thanks for your reply and your response is exactly what i feared!
I am not entirely a novice designer.I just haven't worked on high-speed designs. This is a side project, so i am not rushed for time. Even if i can't get it to work very well, my goal is to use this project to gain some high-speed design experience and more importantly working with FPGA.
Can you suggest some starting steps that i can take? Would it be a good idea to get a beginner's FPGA kit?

 

[FvM]

You can save a lot of design work by using an FPGA kit with a high-speed interface (like multi channel LVDS) suitable for ADC connection and make a sutable ADC front-end board if you don't want to refer to an existing plug-in board.

 

[KlausST]

Hi,

A FPGA kit is always a good point to start

What experience do you have?

Klaus

 

[curious_77]

Are you referring to something like this?

https://www.analog.com/en/analog-to...high-speed_adc_fifo_evaluation_tools/fca.html

I am an IC Test Engineer. I have C programming experience and also experience designing production test boards for ADCs(high precision,not speed) and power ICs.

 

[Dan Mills]

Have a look at the 'Hermes' SDR project from TAPR, 125MS/s 16 bits (Probably not quite 16 bits ENOB), output is ethernet.
The front end may be of interest.

73 Dan.

 

[curious_77]

The Hermes SDR project will definitely be helpful, especially Mercury module, once i am comfortable with FPGAs.

Can you suggest a good FPGA starter kit?

 

[KlausST]

Hi,

we use a NEXYS3 with XILINX Spartan6 on it.
For us it is quite good, but i can not compare with others.

Hope this helps

Klaus

 

[curious_77]

Thanks!
Can you also suggest any online resource or book which is good for a FPGA beginner?

 

[bigdogguru]

Can you also suggest any online resource or book which is good for a FPGA beginner?

It depends on the HDL you wish to study,

For VHDL:

FPGA Prototyping by VHDL Examples: Xilinx Spartan-3 Version

Circuit Design and Simulation with VHDL

The Designer's Guide to VHDL, Third Edition


For Verilog:

FPGA Prototyping By Verilog Examples: Xilinx Spartan-3 Version

Verilog HDL

Verilog for Digital Design


There are a number of online tutorials available for both VHDL and Verilog, I would recommend Googling for the appropriate keywords.


BigDog