AJ
Andreas Jahn
Tue, Nov 15, 2011 10:19 PM
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope ADC?
With best regards
Andreas
http://www.pa4tim.nl/?p=2482 there you see the schematic and some pictures
( the top one is from the circuit that, i was told, turned out to be a VF
converter)
Fred PA4TIM
I am looking now for a converter with less noise.
So what ADC are You using?
Now I have a 26 bit ( 24 bit usable) ADC waiting to be used interfaced
to the arduino, I am making/experimenting with some Vrefs and have parts
for a compound chopper based on a LT1052. But the realisation will be up
in the future, first gathering more knowledge about percision and micro
volt techniques.
Fred PA4TIM
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope ADC?
With best regards
Andreas
>
> http://www.pa4tim.nl/?p=2482 there you see the schematic and some pictures
> ( the top one is from the circuit that, i was told, turned out to be a VF
> converter)
>
> Fred PA4TIM
>
>> I am looking now for a converter with less noise.
>> So what ADC are You using?
>>
>>>
>>> Now I have a 26 bit ( 24 bit usable) ADC waiting to be used interfaced
>>> to the arduino, I am making/experimenting with some Vrefs and have parts
>>> for a compound chopper based on a LT1052. But the realisation will be up
>>> in the future, first gathering more knowledge about percision and micro
>>> volt techniques.
>>>
>>> Fred PA4TIM
F
Fred
Wed, Nov 16, 2011 12:20 AM
The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
the pcb and will make the software for me.
About the dual slope experiment. I could look better as it is. The
arduino died before I could do more tests but first results amazed me.
Remember it was just breadboard, no Vref (just resistive divider from
Vcc and, I do not dare to say, but the measurement pictures were taken
after I blew up my last 4066, so I used optocouplers to switch and
strange enough that went very well.
The drift you see in the measurements is more because the powersupply I
measured the voltage from, is not realy stable. Noise I do not know.
The experiment was after a discussion on a Dutch forum. There was some
talk about multimeters and ADCs and the a member who works at ST as an
EE told the top meters used dual slope about how easy it is to make a
dual slope ADC. He told us to just try it on a breadboard and gave some
tips. A few of us including me started experimenting with it and I was
trilled it was so easy to get it working like it did. Was fun too. I'm
now reading a lot of literature and your interesting discussions to
learn more before I build my meter using the LTC2400. So thanks for all
the valuable information. As a beginner I appreciate it very much.
Fred PA4TIM
Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope ADC?
With best regards
Andreas
http://www.pa4tim.nl/?p=2482 there you see the schematic and some pictures
( the top one is from the circuit that, i was told, turned out to be a VF
converter)
Fred PA4TIM
I am looking now for a converter with less noise.
So what ADC are You using?
Now I have a 26 bit ( 24 bit usable) ADC waiting to be used interfaced
to the arduino, I am making/experimenting with some Vrefs and have parts
for a compound chopper based on a LT1052. But the realisation will be up
in the future, first gathering more knowledge about percision and micro
volt techniques.
Fred PA4TIM
The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
the pcb and will make the software for me.
About the dual slope experiment. I could look better as it is. The
arduino died before I could do more tests but first results amazed me.
Remember it was just breadboard, no Vref (just resistive divider from
Vcc and, I do not dare to say, but the measurement pictures were taken
after I blew up my last 4066, so I used optocouplers to switch and
strange enough that went very well.
The drift you see in the measurements is more because the powersupply I
measured the voltage from, is not realy stable. Noise I do not know.
The experiment was after a discussion on a Dutch forum. There was some
talk about multimeters and ADCs and the a member who works at ST as an
EE told the top meters used dual slope about how easy it is to make a
dual slope ADC. He told us to just try it on a breadboard and gave some
tips. A few of us including me started experimenting with it and I was
trilled it was so easy to get it working like it did. Was fun too. I'm
now reading a lot of literature and your interesting discussions to
learn more before I build my meter using the LTC2400. So thanks for all
the valuable information. As a beginner I appreciate it very much.
Fred PA4TIM
Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
> Hello Fred,
>
> I asked for the 26 bit (24 bit usable) ADC.
> Do you really get this (noiseless) resolution with a simple dual slope ADC?
>
> With best regards
>
> Andreas
>
> >
> > http://www.pa4tim.nl/?p=2482 there you see the schematic and some pictures
> > ( the top one is from the circuit that, i was told, turned out to be a VF
> > converter)
> >
> > Fred PA4TIM
> >
> >> I am looking now for a converter with less noise.
> >> So what ADC are You using?
> >>
> >>>
> >>> Now I have a 26 bit ( 24 bit usable) ADC waiting to be used interfaced
> >>> to the arduino, I am making/experimenting with some Vrefs and have parts
> >>> for a compound chopper based on a LT1052. But the realisation will be up
> >>> in the future, first gathering more knowledge about percision and micro
> >>> volt techniques.
> >>>
> >>> Fred PA4TIM
>
>
>
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
SK
Stan Katz
Wed, Nov 16, 2011 1:47 AM
I would think that Ron Tipton's 6 1/2 digit diy DVM, based on LTC2400 and a
statistical pool of Thaler(now Cirrus) VRE305A's would be the baseline
design to beat in this thread's quest for excellence. Yes?
www.tdl-tech.com/hires-vm.pdf
Stan
On Tue, Nov 15, 2011 at 7:20 PM, Fred pa4tim@gmail.com wrote:
The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
the pcb and will make the software for me.
About the dual slope experiment. I could look better as it is. The
arduino died before I could do more tests but first results amazed me.
Remember it was just breadboard, no Vref (just resistive divider from
Vcc and, I do not dare to say, but the measurement pictures were taken
after I blew up my last 4066, so I used optocouplers to switch and
strange enough that went very well.
The drift you see in the measurements is more because the powersupply I
measured the voltage from, is not realy stable. Noise I do not know.
The experiment was after a discussion on a Dutch forum. There was some
talk about multimeters and ADCs and the a member who works at ST as an
EE told the top meters used dual slope about how easy it is to make a
dual slope ADC. He told us to just try it on a breadboard and gave some
tips. A few of us including me started experimenting with it and I was
trilled it was so easy to get it working like it did. Was fun too. I'm
now reading a lot of literature and your interesting discussions to
learn more before I build my meter using the LTC2400. So thanks for all
the valuable information. As a beginner I appreciate it very much.
Fred PA4TIM
Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope
With best regards
Andreas
( the top one is from the circuit that, i was told, turned out to be a
I am looking now for a converter with less noise.
So what ADC are You using?
Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
to the arduino, I am making/experimenting with some Vrefs and have
for a compound chopper based on a LT1052. But the realisation will
in the future, first gathering more knowledge about percision and
volt techniques.
Fred PA4TIM
and follow the instructions there.
I would think that Ron Tipton's 6 1/2 digit diy DVM, based on LTC2400 and a
statistical pool of Thaler(now Cirrus) VRE305A's would be the baseline
design to beat in this thread's quest for excellence. Yes?
www.tdl-tech.com/hires-vm.pdf
Stan
On Tue, Nov 15, 2011 at 7:20 PM, Fred <pa4tim@gmail.com> wrote:
> The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
> the pcb and will make the software for me.
>
> About the dual slope experiment. I could look better as it is. The
> arduino died before I could do more tests but first results amazed me.
> Remember it was just breadboard, no Vref (just resistive divider from
> Vcc and, I do not dare to say, but the measurement pictures were taken
> after I blew up my last 4066, so I used optocouplers to switch and
> strange enough that went very well.
>
> The drift you see in the measurements is more because the powersupply I
> measured the voltage from, is not realy stable. Noise I do not know.
>
> The experiment was after a discussion on a Dutch forum. There was some
> talk about multimeters and ADCs and the a member who works at ST as an
> EE told the top meters used dual slope about how easy it is to make a
> dual slope ADC. He told us to just try it on a breadboard and gave some
> tips. A few of us including me started experimenting with it and I was
> trilled it was so easy to get it working like it did. Was fun too. I'm
> now reading a lot of literature and your interesting discussions to
> learn more before I build my meter using the LTC2400. So thanks for all
> the valuable information. As a beginner I appreciate it very much.
>
> Fred PA4TIM
>
>
> Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
> > Hello Fred,
> >
> > I asked for the 26 bit (24 bit usable) ADC.
> > Do you really get this (noiseless) resolution with a simple dual slope
> ADC?
> >
> > With best regards
> >
> > Andreas
> >
> > >
> > > http://www.pa4tim.nl/?p=2482 there you see the schematic and some
> pictures
> > > ( the top one is from the circuit that, i was told, turned out to be a
> VF
> > > converter)
> > >
> > > Fred PA4TIM
> > >
> > >> I am looking now for a converter with less noise.
> > >> So what ADC are You using?
> > >>
> > >>>
> > >>> Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
> interfaced
> > >>> to the arduino, I am making/experimenting with some Vrefs and have
> parts
> > >>> for a compound chopper based on a LT1052. But the realisation will
> be up
> > >>> in the future, first gathering more knowledge about percision and
> micro
> > >>> volt techniques.
> > >>>
> > >>> Fred PA4TIM
> >
> >
> >
> > _______________________________________________
> > volt-nuts mailing list -- volt-nuts@febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > and follow the instructions there.
>
>
>
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
AJ
Andreas Jahn
Wed, Nov 16, 2011 7:50 AM
Ok Fred,
thats the ADC im currently using too.
Although he has internally a readout of 28 Bits due to noise only 18-19 Bits
are usable.
To further reduce noise you will have to average many measurement values.
On the other side against many other sigma delta chips the LT2400
has very low offset and gain drift over temperature. And the main advantage
is the Overrange feature of +/-12% which makes offset and full scale
adjustment easy.
Im still hoping that someone knows a ADC chip with less noise
and true 0..5V (or even 0..10V) input with the overrange feature.
With best regards
Andreas
----- Original Message -----
From: "Fred" pa4tim@gmail.com
To: "Discussion of precise voltage measurement" volt-nuts@febo.com
Sent: Wednesday, November 16, 2011 1:20 AM
Subject: Re: [volt-nuts] Homebrew DVM
The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
the pcb and will make the software for me.
About the dual slope experiment. I could look better as it is. The
arduino died before I could do more tests but first results amazed me.
Remember it was just breadboard, no Vref (just resistive divider from
Vcc and, I do not dare to say, but the measurement pictures were taken
after I blew up my last 4066, so I used optocouplers to switch and
strange enough that went very well.
The drift you see in the measurements is more because the powersupply I
measured the voltage from, is not realy stable. Noise I do not know.
The experiment was after a discussion on a Dutch forum. There was some
talk about multimeters and ADCs and the a member who works at ST as an
EE told the top meters used dual slope about how easy it is to make a
dual slope ADC. He told us to just try it on a breadboard and gave some
tips. A few of us including me started experimenting with it and I was
trilled it was so easy to get it working like it did. Was fun too. I'm
now reading a lot of literature and your interesting discussions to
learn more before I build my meter using the LTC2400. So thanks for all
the valuable information. As a beginner I appreciateitverymuch.
Fred PA4TIM
Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope
ADC?
With best regards
Andreas
http://www.pa4tim.nl/?p=2482 there you see the schematic and some
pictures
( the top one is from the circuit that, i was told, turned out to be a
VF
converter)
Fred PA4TIM
I am looking now for a converter with less noise.
So what ADC are You using?
Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
interfaced
to the arduino, I am making/experimenting with some Vrefs and have
parts
for a compound chopper based on a LT1052. But the realisation will be
up
in the future, first gathering more knowledge about percision and
micro
volt techniques.
Fred PA4TIM
Ok Fred,
thats the ADC im currently using too.
Although he has internally a readout of 28 Bits due to noise only 18-19 Bits
are usable.
To further reduce noise you will have to average many measurement values.
On the other side against many other sigma delta chips the LT2400
has very low offset and gain drift over temperature. And the main advantage
is the Overrange feature of +/-12% which makes offset and full scale
adjustment easy.
Im still hoping that someone knows a ADC chip with less noise
and true 0..5V (or even 0..10V) input with the overrange feature.
With best regards
Andreas
----- Original Message -----
From: "Fred" <pa4tim@gmail.com>
To: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
Sent: Wednesday, November 16, 2011 1:20 AM
Subject: Re: [volt-nuts] Homebrew DVM
> The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
> the pcb and will make the software for me.
>
> About the dual slope experiment. I could look better as it is. The
> arduino died before I could do more tests but first results amazed me.
> Remember it was just breadboard, no Vref (just resistive divider from
> Vcc and, I do not dare to say, but the measurement pictures were taken
> after I blew up my last 4066, so I used optocouplers to switch and
> strange enough that went very well.
>
> The drift you see in the measurements is more because the powersupply I
> measured the voltage from, is not realy stable. Noise I do not know.
>
> The experiment was after a discussion on a Dutch forum. There was some
> talk about multimeters and ADCs and the a member who works at ST as an
> EE told the top meters used dual slope about how easy it is to make a
> dual slope ADC. He told us to just try it on a breadboard and gave some
> tips. A few of us including me started experimenting with it and I was
> trilled it was so easy to get it working like it did. Was fun too. I'm
> now reading a lot of literature and your interesting discussions to
> learn more before I build my meter using the LTC2400. So thanks for all
> the valuable information. As a beginner I appreciateitverymuch.
>
> Fred PA4TIM
>
>
> Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
>> Hello Fred,
>>
>> I asked for the 26 bit (24 bit usable) ADC.
>> Do you really get this (noiseless) resolution with a simple dual slope
>> ADC?
>>
>> With best regards
>>
>> Andreas
>>
>> >
>> > http://www.pa4tim.nl/?p=2482 there you see the schematic and some
>> > pictures
>> > ( the top one is from the circuit that, i was told, turned out to be a
>> > VF
>> > converter)
>> >
>> > Fred PA4TIM
>> >
>> >> I am looking now for a converter with less noise.
>> >> So what ADC are You using?
>> >>
>> >>>
>> >>> Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
>> >>> interfaced
>> >>> to the arduino, I am making/experimenting with some Vrefs and have
>> >>> parts
>> >>> for a compound chopper based on a LT1052. But the realisation will be
>> >>> up
>> >>> in the future, first gathering more knowledge about percision and
>> >>> micro
>> >>> volt techniques.
>> >>>
>> >>> Fred PA4TIM
>>
>>
>>
>> _______________________________________________
>> volt-nuts mailing list -- volt-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> and follow the instructions there.
>
>
>
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
AJ
Andreas Jahn
Wed, Nov 16, 2011 8:10 AM
Hello Stan,
thanks for the article
he shows some of the key issues with precision A/D converters.
Although with the noise he mixes Vpp with rms values.
On the other side I have bougth recently two VRE3050A-References from
Cirrus.
(speced nearly the same than VRE305A but only usable with lower minimum
power supply voltage)
For the 3uVpp noise I found something around 9uVpp. (0.1-10 Hz)
Whereas on a LT1027C I measure around 1.9uVpp with the same
filter-amplifier.
And even with temperature hysteresis the VRE3050A that I have measured
is much worse than a LT1027 in a 10-40 degree (Celsius) range.
So I would be interested if the VRE305A is much better than the VRE3050A or
if the specs have
changed when renaming the references from Thaler to Cirrus.
Do you have any measurement values of some recently bought Cirrus VRE305?
With best regards
Andreas
----- Original Message -----
From: "Stan Katz" stan.katz.hk@gmail.com
To: pa4tim@gmail.com; "Discussion of precise voltage measurement"
volt-nuts@febo.com
Sent: Wednesday, November 16, 2011 2:47 AM
Subject: Re: [volt-nuts] Homebrew DVM
I would think that Ron Tipton's 6 1/2 digit diy DVM, based on LTC2400 and a
statistical pool of Thaler(now Cirrus) VRE305A's would be the baseline
design to beat in this thread's quest for excellence. Yes?
www.tdl-tech.com/hires-vm.pdf
Stan
On Tue, Nov 15, 2011 at 7:20 PM, Fred pa4tim@gmail.com wrote:
The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
the pcb and will make the software for me.
About the dual slope experiment. I could look better as it is. The
arduino died before I could do more tests but first results amazed me.
Remember it was just breadboard, no Vref (just resistive divider from
Vcc and, I do not dare to say, but the measurement pictures were taken
after I blew up my last 4066, so I used optocouplers to switch and
strange enough that went very well.
The drift you see in the measurements is more because the powersupply I
measured the voltage from, is not realy stable. Noise I do not know.
The experiment was after a discussion on a Dutch forum. There was some
talk about multimeters and ADCs and the a member who works at ST as an
EE told the top meters used dual slope about how easy it is to make a
dual slope ADC. He told us to just try it on a breadboard and gave some
tips. A few of us including me started experimenting with it and I was
trilled it was so easy to get it working like it did. Was fun too. I'm
now reading a lot of literature and your interesting discussions to
learn more before I build my meter using the LTC2400. So thanks for all
the valuable information. As a beginner I appreciateitverymuch.
Fred PA4TIM
Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope
With best regards
Andreas
( the top one is from the circuit that, i was told, turned out to be
a
I am looking now for a converter with less noise.
So what ADC are You using?
Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
to the arduino, I am making/experimenting with some Vrefs and have
for a compound chopper based on a LT1052. But the realisation will
in the future, first gathering more knowledge about percision and
volt techniques.
Fred PA4TIM
and follow the instructions there.
Hello Stan,
thanks for the article
he shows some of the key issues with precision A/D converters.
Although with the noise he mixes Vpp with rms values.
On the other side I have bougth recently two VRE3050A-References from
Cirrus.
(speced nearly the same than VRE305A but only usable with lower minimum
power supply voltage)
For the 3uVpp noise I found something around 9uVpp. (0.1-10 Hz)
Whereas on a LT1027C I measure around 1.9uVpp with the same
filter-amplifier.
And even with temperature hysteresis the VRE3050A that I have measured
is much worse than a LT1027 in a 10-40 degree (Celsius) range.
So I would be interested if the VRE305A is much better than the VRE3050A or
if the specs have
changed when renaming the references from Thaler to Cirrus.
Do you have any measurement values of some recently bought Cirrus VRE305?
With best regards
Andreas
----- Original Message -----
From: "Stan Katz" <stan.katz.hk@gmail.com>
To: <pa4tim@gmail.com>; "Discussion of precise voltage measurement"
<volt-nuts@febo.com>
Sent: Wednesday, November 16, 2011 2:47 AM
Subject: Re: [volt-nuts] Homebrew DVM
>I would think that Ron Tipton's 6 1/2 digit diy DVM, based on LTC2400 and a
> statistical pool of Thaler(now Cirrus) VRE305A's would be the baseline
> design to beat in this thread's quest for excellence. Yes?
> www.tdl-tech.com/hires-vm.pdf
>
> Stan
>
> On Tue, Nov 15, 2011 at 7:20 PM, Fred <pa4tim@gmail.com> wrote:
>
>> The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
>> the pcb and will make the software for me.
>>
>> About the dual slope experiment. I could look better as it is. The
>> arduino died before I could do more tests but first results amazed me.
>> Remember it was just breadboard, no Vref (just resistive divider from
>> Vcc and, I do not dare to say, but the measurement pictures were taken
>> after I blew up my last 4066, so I used optocouplers to switch and
>> strange enough that went very well.
>>
>> The drift you see in the measurements is more because the powersupply I
>> measured the voltage from, is not realy stable. Noise I do not know.
>>
>> The experiment was after a discussion on a Dutch forum. There was some
>> talk about multimeters and ADCs and the a member who works at ST as an
>> EE told the top meters used dual slope about how easy it is to make a
>> dual slope ADC. He told us to just try it on a breadboard and gave some
>> tips. A few of us including me started experimenting with it and I was
>> trilled it was so easy to get it working like it did. Was fun too. I'm
>> now reading a lot of literature and your interesting discussions to
>> learn more before I build my meter using the LTC2400. So thanks for all
>> the valuable information. As a beginner I appreciateitverymuch.
>>
>> Fred PA4TIM
>>
>>
>> Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
>> > Hello Fred,
>> >
>> > I asked for the 26 bit (24 bit usable) ADC.
>> > Do you really get this (noiseless) resolution with a simple dual slope
>> ADC?
>> >
>> > With best regards
>> >
>> > Andreas
>> >
>> > >
>> > > http://www.pa4tim.nl/?p=2482 there you see the schematic and some
>> pictures
>> > > ( the top one is from the circuit that, i was told, turned out to be
>> > > a
>> VF
>> > > converter)
>> > >
>> > > Fred PA4TIM
>> > >
>> > >> I am looking now for a converter with less noise.
>> > >> So what ADC are You using?
>> > >>
>> > >>>
>> > >>> Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
>> interfaced
>> > >>> to the arduino, I am making/experimenting with some Vrefs and have
>> parts
>> > >>> for a compound chopper based on a LT1052. But the realisation will
>> be up
>> > >>> in the future, first gathering more knowledge about percision and
>> micro
>> > >>> volt techniques.
>> > >>>
>> > >>> Fred PA4TIM
>> >
>> >
>> >
>> > _______________________________________________
>> > volt-nuts mailing list -- volt-nuts@febo.com
>> > To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> > and follow the instructions there.
>>
>>
>>
>> _______________________________________________
>> volt-nuts mailing list -- volt-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> and follow the instructions there.
>>
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
SK
Stan Katz
Wed, Nov 16, 2011 9:48 PM
Hi Andreas,
I own no VRE305A references. However, if you take a look at a co-marketing
article between TI and Thaler in the Nov. 1999 TI Applications Journal, the
typical noise spec for the VRE3050 back then was listed as 3uv between
.1-10hz, just as good as the VRE305A references Tipton used. However, when
one looks at the noise specs in the datasheets for VRE3050 on the current
Cirrus site, and at the original Thaler datasheets for VRE305/VRE3050 the
maximum/minimum noise specs bounding the 3uv typical are unspecified. I
find this unusual for such a pricey unit.
Stan
On Wed, Nov 16, 2011 at 3:10 AM, Andreas Jahn Andreas_-_Jahn@t-online.dewrote:
Hello Stan,
thanks for the article
he shows some of the key issues with precision A/D converters.
Although with the noise he mixes Vpp with rms values.
On the other side I have bougth recently two VRE3050A-References from
Cirrus.
(speced nearly the same than VRE305A but only usable with lower minimum
power supply voltage)
For the 3uVpp noise I found something around 9uVpp. (0.1-10 Hz)
Whereas on a LT1027C I measure around 1.9uVpp with the same
filter-amplifier.
And even with temperature hysteresis the VRE3050A that I have measured
is much worse than a LT1027 in a 10-40 degree (Celsius) range.
So I would be interested if the VRE305A is much better than the VRE3050A
or if the specs have
changed when renaming the references from Thaler to Cirrus.
Do you have any measurement values of some recently bought Cirrus VRE305?
With best regards
Andreas
----- Original Message ----- From: "Stan Katz" stan.katz.hk@gmail.com
To: pa4tim@gmail.com; "Discussion of precise voltage measurement" <
volt-nuts@febo.com>
Sent: Wednesday, November 16, 2011 2:47 AM
Subject: Re: [volt-nuts] Homebrew DVM
I would think that Ron Tipton's 6 1/2 digit diy DVM, based on LTC2400 and
a
statistical pool of Thaler(now Cirrus) VRE305A's would be the baseline
design to beat in this thread's quest for excellence. Yes?
www.tdl-tech.com/hires-vm.pdf
Stan
On Tue, Nov 15, 2011 at 7:20 PM, Fred pa4tim@gmail.com wrote:
The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
the pcb and will make the software for me.
About the dual slope experiment. I could look better as it is. The
arduino died before I could do more tests but first results amazed me.
Remember it was just breadboard, no Vref (just resistive divider from
Vcc and, I do not dare to say, but the measurement pictures were taken
after I blew up my last 4066, so I used optocouplers to switch and
strange enough that went very well.
The drift you see in the measurements is more because the powersupply I
measured the voltage from, is not realy stable. Noise I do not know.
The experiment was after a discussion on a Dutch forum. There was some
talk about multimeters and ADCs and the a member who works at ST as an
EE told the top meters used dual slope about how easy it is to make a
dual slope ADC. He told us to just try it on a breadboard and gave some
tips. A few of us including me started experimenting with it and I was
trilled it was so easy to get it working like it did. Was fun too. I'm
now reading a lot of literature and your interesting discussions to
learn more before I build my meter using the LTC2400. So thanks for all
the valuable information. As a beginner I appreciateitverymuch.
Fred PA4TIM
Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
Hello Fred,
I asked for the 26 bit (24 bit usable) ADC.
Do you really get this (noiseless) resolution with a simple dual slope
With best regards
Andreas
( the top one is from the circuit that, i was told, turned out to be
a
I am looking now for a converter with less noise.
So what ADC are You using?
Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
to the arduino, I am making/experimenting with some Vrefs and have
for a compound chopper based on a LT1052. But the realisation will
in the future, first gathering more knowledge about percision and
volt techniques.
Fred PA4TIM
and follow the instructions there.
Hi Andreas,
I own no VRE305A references. However, if you take a look at a co-marketing
article between TI and Thaler in the Nov. 1999 TI Applications Journal, the
typical noise spec for the VRE3050 back then was listed as 3uv between
.1-10hz, just as good as the VRE305A references Tipton used. However, when
one looks at the noise specs in the datasheets for VRE3050 on the current
Cirrus site, and at the original Thaler datasheets for VRE305/VRE3050 the
maximum/minimum noise specs bounding the 3uv typical are unspecified. I
find this unusual for such a pricey unit.
Stan
On Wed, Nov 16, 2011 at 3:10 AM, Andreas Jahn <Andreas_-_Jahn@t-online.de>wrote:
> Hello Stan,
>
> thanks for the article
> he shows some of the key issues with precision A/D converters.
> Although with the noise he mixes Vpp with rms values.
>
> On the other side I have bougth recently two VRE3050A-References from
> Cirrus.
> (speced nearly the same than VRE305A but only usable with lower minimum
> power supply voltage)
> For the 3uVpp noise I found something around 9uVpp. (0.1-10 Hz)
> Whereas on a LT1027C I measure around 1.9uVpp with the same
> filter-amplifier.
> And even with temperature hysteresis the VRE3050A that I have measured
> is much worse than a LT1027 in a 10-40 degree (Celsius) range.
>
> So I would be interested if the VRE305A is much better than the VRE3050A
> or if the specs have
> changed when renaming the references from Thaler to Cirrus.
> Do you have any measurement values of some recently bought Cirrus VRE305?
>
> With best regards
>
> Andreas
>
> ----- Original Message ----- From: "Stan Katz" <stan.katz.hk@gmail.com>
> To: <pa4tim@gmail.com>; "Discussion of precise voltage measurement" <
> volt-nuts@febo.com>
> Sent: Wednesday, November 16, 2011 2:47 AM
>
> Subject: Re: [volt-nuts] Homebrew DVM
>
>
> I would think that Ron Tipton's 6 1/2 digit diy DVM, based on LTC2400 and
>> a
>> statistical pool of Thaler(now Cirrus) VRE305A's would be the baseline
>> design to beat in this thread's quest for excellence. Yes?
>> www.tdl-tech.com/hires-vm.pdf
>>
>> Stan
>>
>> On Tue, Nov 15, 2011 at 7:20 PM, Fred <pa4tim@gmail.com> wrote:
>>
>> The ADC I am gonna use is the LTC2400. A friend who is a digit-nut made
>>> the pcb and will make the software for me.
>>>
>>> About the dual slope experiment. I could look better as it is. The
>>> arduino died before I could do more tests but first results amazed me.
>>> Remember it was just breadboard, no Vref (just resistive divider from
>>> Vcc and, I do not dare to say, but the measurement pictures were taken
>>> after I blew up my last 4066, so I used optocouplers to switch and
>>> strange enough that went very well.
>>>
>>> The drift you see in the measurements is more because the powersupply I
>>> measured the voltage from, is not realy stable. Noise I do not know.
>>>
>>> The experiment was after a discussion on a Dutch forum. There was some
>>> talk about multimeters and ADCs and the a member who works at ST as an
>>> EE told the top meters used dual slope about how easy it is to make a
>>> dual slope ADC. He told us to just try it on a breadboard and gave some
>>> tips. A few of us including me started experimenting with it and I was
>>> trilled it was so easy to get it working like it did. Was fun too. I'm
>>> now reading a lot of literature and your interesting discussions to
>>> learn more before I build my meter using the LTC2400. So thanks for all
>>> the valuable information. As a beginner I appreciateitverymuch.
>>>
>>> Fred PA4TIM
>>>
>>>
>>> Andreas Jahn schreef op di 15-11-2011 om 23:19 [+0100]:
>>> > Hello Fred,
>>> >
>>> > I asked for the 26 bit (24 bit usable) ADC.
>>> > Do you really get this (noiseless) resolution with a simple dual slope
>>> ADC?
>>> >
>>> > With best regards
>>> >
>>> > Andreas
>>> >
>>> > >
>>> > > http://www.pa4tim.nl/?p=2482 there you see the schematic and some
>>> pictures
>>> > > ( the top one is from the circuit that, i was told, turned out to be
>>> > > a
>>> VF
>>> > > converter)
>>> > >
>>> > > Fred PA4TIM
>>> > >
>>> > >> I am looking now for a converter with less noise.
>>> > >> So what ADC are You using?
>>> > >>
>>> > >>>
>>> > >>> Now I have a 26 bit ( 24 bit usable) ADC waiting to be used
>>> interfaced
>>> > >>> to the arduino, I am making/experimenting with some Vrefs and have
>>> parts
>>> > >>> for a compound chopper based on a LT1052. But the realisation will
>>> be up
>>> > >>> in the future, first gathering more knowledge about percision and
>>> micro
>>> > >>> volt techniques.
>>> > >>>
>>> > >>> Fred PA4TIM
>>> >
>>> >
>>> >
>>> > ______________________________**_________________
>>> > volt-nuts mailing list -- volt-nuts@febo.com
>>> > To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/**mailman/listinfo/volt-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts>
>>> > and follow the instructions there.
>>>
>>>
>>>
>>> ______________________________**_________________
>>> volt-nuts mailing list -- volt-nuts@febo.com
>>> To unsubscribe, go to
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>>> and follow the instructions there.
>>>
>>> ______________________________**_________________
>> volt-nuts mailing list -- volt-nuts@febo.com
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>
>
> ______________________________**_________________
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