Products > Test Equipment
AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter
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kalel:

--- Quote from: BroMarduk on August 03, 2017, 04:50:54 am ---
--- Quote from: coromonadalix on July 30, 2017, 06:39:49 pm ---There is a new model look a like : SURPEER AV4     it is a 20000 counts model ???? maybe worth checking ? sure it is not a 20$ meter ...

on Ebay: http://www.ebay.com/itm/digital-multimeter-true-rms-4-1-2-voltmeter-with-auto-range-multi-meter/112444656128?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D41376%26meid%3Dbdba934ac7de4c11bf5d7231a7c8164c%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D152355178736

--- End quote ---

I received an HY-19E from China (Banggood - 39.99 USD) that appears to be the same model (except in green).  Haven't tested it yet, but will soon.   Build quality is on par with the larger Aneng meters - which means just slightly below average.

--- End quote ---

Let us know how it is. 20000 count. :)
floobydust:

--- Quote from: RedSky on August 02, 2017, 02:30:43 am ---...   Virtually no chance this thing has a 13+bit ADC in it... yet it's trying to do 10,000 resolution has to be a fair amount of averaging going on.

--- End quote ---
The resolution is already here for DMM's.
The Hycon HY12P65 DMM IC has ?? A/D 18-bit at medium sample rate for 99,999 counts( bi-polar) capability.
Dream Tech's firmware is chopping this down, because crippling features is needed I guess. The 4-digit LCD display is the limiting factor to 9,999 counts.
That built-in MCU limiting factor is its 4MHz clock and 6KB code-space is pretty tight, although what's a little assembly language...

I'm tempted make a DMM with HY3131 the analog front end with 24-bit A/D. HY3130 is 16-bit A/D for 50,000 count applications.

I'll bet the AN8002, AN8004 use the same DMM IC and firmware. People have upped the "max. counts" EEPROM number and accessed the higher resolution.
But you have to recalibrate and tronde says some True-RMS hassles. There's a few other EEPROM settings to play with.
Probably the internal voltage reference is poor and so the AN8008 went to an external Vref IC.

crazyguy:

--- Quote from: floobydust on August 04, 2017, 02:07:44 am ---
--- Quote from: RedSky on August 02, 2017, 02:30:43 am ---...   Virtually no chance this thing has a 13+bit ADC in it... yet it's trying to do 10,000 resolution has to be a fair amount of averaging going on.

--- End quote ---
The resolution is already here for DMM's.
The Hycon HY12P65 DMM IC has ?? A/D 18-bit at medium sample rate for 99,999 counts( bi-polar) capability.
Dream Tech's firmware is chopping this down, because crippling features is needed I guess. The 4-digit LCD display is the limiting factor to 9,999 counts.
That built-in MCU limiting factor is its 4MHz clock and 6KB code-space is pretty tight, although what's a little assembly language...

I'm tempted make a DMM with HY3131 the analog front end with 24-bit A/D. HY3130 is 16-bit A/D for 50,000 count applications.

 
I'll bet the AN8002, AN8004 use the same DMM IC and firmware. People have upped the "max. counts" EEPROM number and accessed the higher resolution.
But you have to recalibrate and tronde says some True-RMS hassles. There's a few other EEPROM settings to play with.
Probably the internal voltage reference is poor and so the AN8008 went to an external Vref IC.

--- End quote ---

In practical, due to the noise and distortion in the ADC circuity, the ENOB (effective number of bits) must be less than ADC specified number of bits.

Resolution vs. ENOB – Still Hazy After All These Years
http://www.analog.com/en/analog-dialogue/raqs/raq-issue-90.html

HY12P65 ENOB Test Tool User Manual
http://www.hycontek.com/wp-content/uploads/APD-DMM004_EN.pdf
floobydust:
HY12P6x ENOB is given as 19-bit and Eval board has 6-digit LCD. I think the test software is to verify performance, do FFT of the noise.

Hard to know what the signal/noise ratio of the input amp, A/D, reference etc. will be and what you can improve with digital filtering and over-sampling, noise shaping.
I guess that can improve ENOB.

So how many usable A/D bits do we have? 
crazyguy:

--- Quote from: floobydust on August 04, 2017, 04:24:29 am ---HY12P6x ENOB is given as 19-bit and Eval board has 6-digit LCD. I think the test software is to verify performance, do FFT of the noise.

Hard to know what the signal/noise ratio of the input amp, A/D, reference etc. will be and what you can improve with digital filtering and over-sampling, noise shaping.
I guess that can improve ENOB.

So how many usable A/D bits do we have?

--- End quote ---

you modified the decoupling capacitors on your meter, already improved the SNR -> improved the ENOB a little bit.
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