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Digital Analog converter for resonator circuit

Started by chess August 10, 2015
Hi
I have dual resonator circuit consists of Inductors, capacitors and
resistors. I am generating sine wave with amplitude of 1 from DAC and
write a frequency sweep function in Matlab however I only get a  single
resonator response and I am missing the second peak. when I connect 1 ohm
or any value less than that in parallel with DAC I am able to get both
peaks. I can also get both peak when I am not connecting any resistors in
parallel with DAC but I changed the amplitude of my sine waves to 0.02 or
less.
What do you guys think is causing this problem that I cannot get both peak
with sine wave amplitude 1 with no resistors in parallel  ?

DAC has output impedance of 0.5 ohm

current driven =5 mA 
overdriven current =20mA


---------------------------------------
Posted through http://www.Electronics-Related.com
On 8/10/2015 10:04 PM, chess wrote:
> Hi > I have dual resonator circuit consists of Inductors, capacitors and > resistors. I am generating sine wave with amplitude of 1 from DAC and > write a frequency sweep function in Matlab however I only get a single > resonator response and I am missing the second peak. when I connect 1 ohm > or any value less than that in parallel with DAC I am able to get both > peaks. I can also get both peak when I am not connecting any resistors in > parallel with DAC but I changed the amplitude of my sine waves to 0.02 or > less. > What do you guys think is causing this problem that I cannot get both peak > with sine wave amplitude 1 with no resistors in parallel ? > > DAC has output impedance of 0.5 ohm > > current driven =5 mA > overdriven current =20mA >
How about a schematic of both connections? Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
On Mon, 10 Aug 2015 21:04:35 -0500, chess wrote:

> Hi I have dual resonator circuit consists of Inductors, capacitors and > resistors. I am generating sine wave with amplitude of 1 from DAC and > write a frequency sweep function in Matlab however I only get a single > resonator response and I am missing the second peak. when I connect 1 > ohm or any value less than that in parallel with DAC I am able to get > both peaks. I can also get both peak when I am not connecting any > resistors in parallel with DAC but I changed the amplitude of my sine > waves to 0.02 or less. > What do you guys think is causing this problem that I cannot get both > peak with sine wave amplitude 1 with no resistors in parallel ? > > DAC has output impedance of 0.5 ohm
It sounds like the output impedance isn't really 0.5 ohm, or isn't 0.5 ohm at the frequency of your missing peak. Read the data sheet carefully -- if they say 0.5 ohm _at DC_ that'll be a big clue. -- www.wescottdesign.com
On Mon, 10 Aug 2015 22:10:59 -0400, Phil Hobbs wrote:

> On 8/10/2015 10:04 PM, chess wrote: >> Hi I have dual resonator circuit consists of Inductors, capacitors and >> resistors. I am generating sine wave with amplitude of 1 from DAC and >> write a frequency sweep function in Matlab however I only get a single >> resonator response and I am missing the second peak. when I connect 1 >> ohm or any value less than that in parallel with DAC I am able to get >> both peaks. I can also get both peak when I am not connecting any >> resistors in parallel with DAC but I changed the amplitude of my sine >> waves to 0.02 or less. >> What do you guys think is causing this problem that I cannot get both >> peak with sine wave amplitude 1 with no resistors in parallel ? >> >> DAC has output impedance of 0.5 ohm >> >> current driven =5 mA overdriven current =20mA >> >> > > How about a schematic of both connections? > > Cheers > > Phil Hobbs
Including the DAC part number. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
>On Mon, 10 Aug 2015 21:04:35 -0500, chess wrote: > >> Hi I have dual resonator circuit consists of Inductors, capacitors and >> resistors. I am generating sine wave with amplitude of 1 from DAC and >> write a frequency sweep function in Matlab however I only get a
single
>> resonator response and I am missing the second peak. when I connect 1 >> ohm or any value less than that in parallel with DAC I am able to get >> both peaks. I can also get both peak when I am not connecting any >> resistors in parallel with DAC but I changed the amplitude of my sine >> waves to 0.02 or less. >> What do you guys think is causing this problem that I cannot get both >> peak with sine wave amplitude 1 with no resistors in parallel ? >> >> DAC has output impedance of 0.5 ohm > >It sounds like the output impedance isn't really 0.5 ohm, or isn't 0.5 >ohm at the frequency of your missing peak. > >Read the data sheet carefully -- if they say 0.5 ohm _at DC_ that'll be a
>big clue. > >-- >www.wescottdesign.com
it says output coupling=DC and output impedance is 0.5 ohm.How can I upload image here? --------------------------------------- Posted through http://www.Electronics-Related.com
On Tuesday, 11 August 2015 14:52:13 UTC+10, chess  wrote:
> >On Mon, 10 Aug 2015 21:04:35 -0500, chess wrote: > > > >> Hi I have dual resonator circuit consists of Inductors, capacitors and > >> resistors. I am generating sine wave with amplitude of 1 from DAC and > >> write a frequency sweep function in Matlab however I only get a > >> single > >> resonator response and I am missing the second peak. when I connect 1 > >> ohm or any value less than that in parallel with DAC I am able to get > >> both peaks. I can also get both peak when I am not connecting any > >> resistors in parallel with DAC but I changed the amplitude of my sine > >> waves to 0.02 or less. > >> What do you guys think is causing this problem that I cannot get both > >> peak with sine wave amplitude 1 with no resistors in parallel ? > >> > >> DAC has output impedance of 0.5 ohm > > > >It sounds like the output impedance isn't really 0.5 ohm, or isn't 0.5 > >ohm at the frequency of your missing peak. > > > >Read the data sheet carefully -- if they say 0.5 ohm _at DC_ that'll be a > >big clue. > > > >-- > >www.wescottdesign.com > > it says output coupling=DC and output impedance is 0.5 ohm.How can I > upload image here?
If the DAC is commercially available, it will have a part number and a data sheet. The data sheet will be available on the manufacturer's web-site. Post the url/link to the datasheet. Here's an example of such a link http://www.analog.com/media/en/technical-documentation/data-sheets/AD9142A.pdf It was at the top of the Analog Devices bipolar DAC page and is only an example. -- Bill Sloman, Sydney
>On Tuesday, 11 August 2015 14:52:13 UTC+10, chess wrote: >> >On Mon, 10 Aug 2015 21:04:35 -0500, chess wrote: >> > >> >> Hi I have dual resonator circuit consists of Inductors, capacitors
and
>> >> resistors. I am generating sine wave with amplitude of 1 from DAC
and
>> >> write a frequency sweep function in Matlab however I only get a >> >> single >> >> resonator response and I am missing the second peak. when I connect
1
>> >> ohm or any value less than that in parallel with DAC I am able to
get
>> >> both peaks. I can also get both peak when I am not connecting any >> >> resistors in parallel with DAC but I changed the amplitude of my
sine
>> >> waves to 0.02 or less. >> >> What do you guys think is causing this problem that I cannot get
both
>> >> peak with sine wave amplitude 1 with no resistors in parallel ? >> >> >> >> DAC has output impedance of 0.5 ohm >> > >> >It sounds like the output impedance isn't really 0.5 ohm, or isn't 0.5
>> >ohm at the frequency of your missing peak. >> > >> >Read the data sheet carefully -- if they say 0.5 ohm _at DC_ that'll
be a
> >> >big clue. >> > >> >-- >> >www.wescottdesign.com >> >> it says output couplingÜ and output impedance is 0.5 ohm.How can I >> upload image here? > >If the DAC is commercially available, it will have a part number and a
data
>sheet. The data sheet will be available on the manufacturer's web-site. > >Post the url/link to the datasheet. Here's an example of such a link > >http://www.analog.com/media/en/technical-documentation/data-sheets/AD9142A.pdf > >It was at the top of the Analog Devices bipolar DAC page and is only an >example. > >-- >Bill Sloman, Sydney
This is the DAC datasheet http://www.ni.com/datasheet/pdf/en/ds-10 --------------------------------------- Posted through http://www.Electronics-Related.com
>>On Tuesday, 11 August 2015 14:52:13 UTC+10, chess wrote: >>> >On Mon, 10 Aug 2015 21:04:35 -0500, chess wrote: >>> > >>> >> Hi I have dual resonator circuit consists of Inductors, capacitors >and >>> >> resistors. I am generating sine wave with amplitude of 1 from DAC >and >>> >> write a frequency sweep function in Matlab however I only get a >>> >> single >>> >> resonator response and I am missing the second peak. when I
connect
>1 >>> >> ohm or any value less than that in parallel with DAC I am able to >get >>> >> both peaks. I can also get both peak when I am not connecting any >>> >> resistors in parallel with DAC but I changed the amplitude of my >sine >>> >> waves to 0.02 or less. >>> >> What do you guys think is causing this problem that I cannot get >both >>> >> peak with sine wave amplitude 1 with no resistors in parallel ? >>> >> >>> >> DAC has output impedance of 0.5 ohm >>> > >>> >It sounds like the output impedance isn't really 0.5 ohm, or isn't
0.5
> >>> >ohm at the frequency of your missing peak. >>> > >>> >Read the data sheet carefully -- if they say 0.5 ohm _at DC_ that'll >be a >> >>> >big clue. >>> > >>> >-- >>> >www.wescottdesign.com >>> >>> it says output couplingÜ and output impedance is 0.5 ohm.How can I >>> upload image here? >> >>If the DAC is commercially available, it will have a part number and a >data >>sheet. The data sheet will be available on the manufacturer's web-site. >> >>Post the url/link to the datasheet. Here's an example of such a link >> >>http://www.analog.com/media/en/technical-documentation/data-sheets/AD9142A.pdf >> >>It was at the top of the Analog Devices bipolar DAC page and is only an >>example. >> >>-- >>Bill Sloman, Sydney > >This is the DAC datasheet >http://www.ni.com/datasheet/pdf/en/ds-10 >--------------------------------------- >Posted through http://www.Electronics-Related.com
This is also the my current DAC I am using http://www.ni.com/datasheet/pdf/en/ds-24 --------------------------------------- Posted through http://www.Electronics-Related.com
On Monday, August 10, 2015 at 10:04:39 PM UTC-4, chess wrote:
> Hi > I have dual resonator circuit consists of Inductors, capacitors and > resistors. I am generating sine wave with amplitude of 1 from DAC and > write a frequency sweep function in Matlab however I only get a single > resonator response and I am missing the second peak. when I connect 1 ohm > or any value less than that in parallel with DAC I am able to get both > peaks. I can also get both peak when I am not connecting any resistors in > parallel with DAC but I changed the amplitude of my sine waves to 0.02 or > less. > What do you guys think is causing this problem that I cannot get both peak > with sine wave amplitude 1 with no resistors in parallel ? > > DAC has output impedance of 0.5 ohm > > current driven =5 mA > overdriven current =20mA > > > --------------------------------------- > Posted through http://www.Electronics-Related.com
A schematic of your circuit please. Could be an LTspice file. Or a scribble with picture uploaded to a image hosting site. and link. Maybe you are sweeping too fast through a narrow resonance? George H.
>On Monday, August 10, 2015 at 10:04:39 PM UTC-4, chess wrote: >> Hi >> I have dual resonator circuit consists of Inductors, capacitors and >> resistors. I am generating sine wave with amplitude of 1 from DAC and >> write a frequency sweep function in Matlab however I only get a
single
>> resonator response and I am missing the second peak. when I connect 1
ohm
>> or any value less than that in parallel with DAC I am able to get both >> peaks. I can also get both peak when I am not connecting any resistors
in
>> parallel with DAC but I changed the amplitude of my sine waves to 0.02
or
>> less. >> What do you guys think is causing this problem that I cannot get both >peak >> with sine wave amplitude 1 with no resistors in parallel ? >> >> DAC has output impedance of 0.5 ohm >> >> current driven =5 mA >> overdriven current mA >> >> >> --------------------------------------- >> Posted through http://www.Electronics-Related.com > >A schematic of your circuit please. Could be an LTspice file. >Or a scribble with picture uploaded to a image hosting site. and link. > >Maybe you are sweeping too fast through a narrow resonance? > >George H.
no I am not sweeping fast. The peaks should be apart by 5KhZ and my step size for frequency sweep is 100 Hz. --------------------------------------- Posted through http://www.Electronics-Related.com