gentlevoice1

1 bit to 32 bit converter IC?
« on: May 17, 2013, 02:28:20 PM »
Hey diy'ers  ;)

I may soon be about to convert a relatively high-speed 1 bit signal (~25 MHz) to a 32 bit/ 384 kHz code (I2S output).

However, I don't know if such an IC (superb quality needed) exists and what its generic technical name would be. First I searched for multiplexing devices but so it isn't ... Is there any name for such a device & might you have a suggestion for a particular device?

I'll appreciate your inputs!

Jesper

" ... Sustainability matters to me also in my audio endeavors ... "


Rochey

Re: 1 bit to 32 bit converter IC?
« Reply #1 on: May 17, 2013, 02:34:04 PM »
Jesper, is the source dsd? What's the bit rate? Pcm4204 did something similar to this.
Expat Audio Home: http://www.expataudio.com

gentlevoice1

Re: 1 bit to 32 bit converter IC?
« Reply #2 on: May 17, 2013, 04:27:54 PM »
Hey Rochey,

Quote
Jesper, is the source dsd? What's the bit rate? Pcm4204 did something similar to this.

Yes, eventually it's DSD and with a 512 Fs bitrate (22.476 MHz). I just haven't been able to find an appropriate PC interface card that can transfer this signal to a PC directly so now I hope to use this one:

http://www.rigisystems.net/index.php/usbpalen.html

.. but then needs to "convert" the 1 bit signal to 32bits/384 kHz.

Do you know what such a device is called?

Greetings from over here,

Jesper
" ... Sustainability matters to me also in my audio endeavors ... "

Rochey

Re: 1 bit to 32 bit converter IC?
« Reply #3 on: May 17, 2013, 06:10:33 PM »
Yes, an fpga. ;)
Expat Audio Home: http://www.expataudio.com

gentlevoice1

Re: 1 bit to 32 bit converter IC?
« Reply #4 on: May 18, 2013, 04:12:31 AM »
Noooooo  .... you can't be serious about that  :o  .... FPGAs appear to be quite time-consuming to get to know ... No other options at all?

 ;) Jesper

" ... Sustainability matters to me also in my audio endeavors ... "

Re: 1 bit to 32 bit converter IC?
« Reply #5 on: May 18, 2013, 07:24:46 PM »
http://books.google.es/books?id=g-TBaAyAwQ4C&lpg=PP1&pg=PP1#v=onepage&q&f=false

A book about one of the languages (VHDL) you can use to programme FPGAs. I just read through it over the past few days. It was my first contact with VHDL or hardware design beyond basic logic ICs, but I think what you're asking would be doable without years of practice. Depending on your background of course.

gentlevoice1

Re: 1 bit to 32 bit converter IC?
« Reply #6 on: May 20, 2013, 02:11:59 AM »
Hi niklasni1,

Hmmmm... interesting link you posted - thanks  ;) I am currently considering learning how to program an FPGA, however, am sort of "cautious" in moving in that direction as I reckon it may take some time to learn. On the other hand I have no doubt that it'll open up many interesting doors when I get to the point of actually being able to do so. And I may just skim through e.g. the book you suggest to get an idea about what I can expect.

BTW other sources for VHDL & FPGA programming may be:

Circuit Design with VHDL (Volnei A. Pedroni)

FPGA Prototyping by VHDL Examples (Pong P. Chu)

If you are interested there are reviews of them on Amazon.

Thanks again for replying  :)

Jesper



" ... Sustainability matters to me also in my audio endeavors ... "

Andy Peters

Re: 1 bit to 32 bit converter IC?
« Reply #7 on: May 20, 2013, 01:08:42 PM »
Hey diy'ers  ;)

I may soon be about to convert a relatively high-speed 1 bit signal (~25 MHz) to a 32 bit/ 384 kHz code (I2S output).

However, I don't know if such an IC (superb quality needed) exists and what its generic technical name would be. First I searched for multiplexing devices but so it isn't ... Is there any name for such a device & might you have a suggestion for a particular device?

You need a shift register.

The most reasonable way to do it is in a CPLD or an FPGA, especially if it's part of a larger design.

The shift register itself is about six lines of VHDL.

The implementation is left as an exercise for the reader :)

-a
"On the Internet, nobody can hear you mix a band"

gentlevoice1

Re: 1 bit to 32 bit converter IC?
« Reply #8 on: May 21, 2013, 02:50:45 AM »
Quote
... The implementation is left as an exercise for the reader ...

 :o ... In Danish we might say something like "hø, hø" which is a slight smile/laughter implying that we are aware that this may not be entirely simple - although it might appear so ...

Hmm... Andy, can I ask you this: To program an FPGA is VHDL the most sensible language to use? Or would it e.g. make more sense to program it using C++ or something else? I'm asking without knowing because I have no previous experience with programming so will need to start from scratch.

Eventually my aims are two-fold:

1. To be able to transfer high speed 1 bit signals to a PC in a suitable format.

2. To transfer high speed 1 bit signals to a storage card - this entity will be complete disconnected from a computer (in the long term the preferred option).

I reckon there are many ways of doing this, however, I would like to move in a direction that is as future oriented as possible, that is, the programming language and the hardware platform chosen is likely to be used also in the years to come.

Do you know if an FPGA would be the way to go? And if so, which platform/device?

Thanks for reading and appreciation of any insights you may have  ;)

Jesper





« Last Edit: May 21, 2013, 02:55:41 AM by gentlevoice1 »
" ... Sustainability matters to me also in my audio endeavors ... "

Andy Peters

Re: 1 bit to 32 bit converter IC?
« Reply #9 on: May 21, 2013, 04:06:07 PM »
Hmm... Andy, can I ask you this: To program an FPGA is VHDL the most sensible language to use? Or would it e.g. make more sense to program it using C++ or something else? I'm asking without knowing because I have no previous experience with programming so will need to start from scratch.

Let me be pedantic here for the moment.

You don't "program an FPGA in VHDL" or any other language, for that matter. You describe your digital logic using a hardware-description language (generally either VHDL or Verilog). Remember that FPGA design is digital logic design. That your design is implemented in one big chip rather than a board full of 74xxx TTL parts is a detail.

Having said that: there is this effort underway by the big EDA companies to push a "high-level synthesis" approach to FPGA design. The tools take code written in C or C++ and (attempt to) synthesize it down to FPGA resources. The tools are expensive and are limited to certain subsets of design problems. They are best avoided unless you want to annoy yourself.

Pick up one of the cheap Xilinx or Altera starter kits as well as a copy of Peter Ashenden's "Designer's Guide To VHDL" and start from there.

Quote
Eventually my aims are two-fold:
 (snip)

Do you know if an FPGA would be the way to go? And if so, which platform/device?

It probably is. Which device? hmm ... I tend to use Xilinx Spartan 3AN devices for anything that makes sense. The design tends to drive the device selection, though.

-a
"On the Internet, nobody can hear you mix a band"


gentlevoice1

Re: 1 bit to 32 bit converter IC?
« Reply #10 on: May 23, 2013, 03:43:22 PM »
Hi Andy,

& thank you for answering and elaborating on my questions.

I've been around Peter Ashenden's book on Amazon (read an excerpt) and also read excerpts in the books I mention in a previous post in this thread. And my conclusion right now is that I haven't got the energy to take on learning how to program an FPGA - at least not on my own hand. I reckon that learning FPGA programming - like so many other new fields - may be a path filled with interesting discoveries and possibilities, yet also with myriad "unforeseens".

So, I'd rather focus on the other processes underways (D/A & A/D converters, output stages, electrostatic headphone, PSUs etc.) and then seek for someone who is able to help program the FPGA/suitable device.

Nevertheless, I appreciate your feedback and should time allow for learning FPGA programming skills onwards I now have a thread's information to start out from.

Greetings,

Jesper

P.S.: I've also sent you a PM.
" ... Sustainability matters to me also in my audio endeavors ... "


 

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