stupid idea: nixie peak level display
« on: September 04, 2016, 06:08:28 PM »
I wan to build a numeric peak hold level display. Preferrably from a PCM source, but analogue would be possible as well.
So it should read the highest dB value encountered since the last reset.

For the beauty of it, I want to realise the display itself with nixie tubes.

This is just a drunken idea that came up last night... any idea of what "easy" approaches would be suitable? I have no experoence in D S P so far.

thanks,

georg


JohnRoberts

Re: stupid idea: nixie peak level display
« Reply #1 on: September 04, 2016, 10:25:19 PM »
 ;D  Have another beer...

You want it to read out  numerical dB?

You don't need dsp for a simple meter but a microprocessor would help crunch the level in numerical dB.

JR
John Roberts
http://circularscience.com
Tune it, or don't play it...

MrDude

Re: stupid idea: nixie peak level display
« Reply #2 on: September 06, 2016, 05:51:51 AM »
Hi,

I recently watched these two videos about nixie tubes, I found them very informative.

I know, this is not the direct solution to your problem but it may help your design with nixie tubes.


https://www.youtube.com/watch?v=jytF5bvPGcU

https://www.youtube.com/watch?v=yAx4ehqRSPE

Re: stupid idea: nixie peak level display
« Reply #3 on: September 06, 2016, 06:24:30 AM »
Thanks for the input

So the steps would be:

- decode AES signal to PCM
- analyze PCM data
- calculate dB value
- update & hold highest value until reset
- display output

Hm I fear I need to ask some programmer friends :)

Rochey

Re: stupid idea: nixie peak level display
« Reply #4 on: September 06, 2016, 01:01:18 PM »
DIR9001 + PCM3070 running a miniDSP Process flow that will do your level detection, then use an MSP430 or PIC to read the values from the PCM3070 and light up your nixies.

Expat Audio Home: http://www.expataudio.com

Andy Peters

Re: stupid idea: nixie peak level display
« Reply #5 on: September 06, 2016, 01:44:35 PM »
DIR9001 + PCM3070 running a miniDSP Process flow that will do your level detection, then use an MSP430 or PIC to read the values from the PCM3070 and light up your nixies.

Or use a micro with I2S port and skip the conversion stage.

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

Rochey

Re: stupid idea: nixie peak level display
« Reply #6 on: September 07, 2016, 03:12:14 PM »
DIR9001 + PCM3070 running a miniDSP Process flow that will do your level detection, then use an MSP430 or PIC to read the values from the PCM3070 and light up your nixies.

Or use a micro with I2S port and skip the conversion stage.

-a

I wasn't even thinking of using the converters in the  PCM3070. I was thinking of the miniDSP that's inside it and having it do the weighted averaging etc.

Plus, which small and simple micro's have I2S ports on them?

/R
Expat Audio Home: http://www.expataudio.com

JohnRoberts

Re: stupid idea: nixie peak level display
« Reply #7 on: September 07, 2016, 05:12:50 PM »
DIR9001 + PCM3070 running a miniDSP Process flow that will do your level detection, then use an MSP430 or PIC to read the values from the PCM3070 and light up your nixies.

Or use a micro with I2S port and skip the conversion stage.

-a

I wasn't even thinking of using the converters in the  PCM3070. I was thinking of the miniDSP that's inside it and having it do the weighted averaging etc.

Plus, which small and simple micro's have I2S ports on them?

/R
The microchip pic I used have I2s but is suspect most do...

What kind of weighted averaging do you need for a peak hold? PPM is something like 4mSec attack which isn't that hard to do (I've done that on simple RISC platform along with other stupid meter tricks).

I haven't tried to strip levels from AES digital but probably not rocket science.


JR
John Roberts
http://circularscience.com
Tune it, or don't play it...

Andy Peters

Re: stupid idea: nixie peak level display
« Reply #8 on: September 07, 2016, 08:00:24 PM »
Plus, which small and simple micro's have I2S ports on them?

ARM Cortex M0s and AVR32, for example. Is the M0 as simple as an MSP430? No. Is it cheap? Hell yeah.
"On the Internet, nobody can hear you mix a band"

PRR

Re: stupid idea: nixie peak level display
« Reply #9 on: September 18, 2016, 09:22:11 PM »
> numeric peak hold level display. ...analogue would be possible..., I want to realise the display itself with nixie tubes.

How is this different from an early Nixie DVM?

OK, you ask for a fancier AD/DC converter than most bench meters. And you want a LOG conversion in front. For modest shirt-sleeve accuracy, a couple diodes will do.

Heath made a 2-1/2 digit Nixie DMM. Simple, elegant.

H-P and all the big boys made Nixie DMMs for a while.

eBay!


Re: stupid idea: nixie peak level display
« Reply #10 on: September 19, 2016, 01:32:22 AM »
Heath made a 2-1/2 digit Nixie DMM. Simple, elegant.

They certainly did, model IM-1202.

Might be just the thing.

Gene