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

# Digital Analog converter for resonator circuit

Started by ●August 10, 2015

Reply by ●August 10, 20152015-08-10

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

Reply by ●August 10, 20152015-08-10

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 ohmIt 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

Reply by ●August 11, 20152015-08-11

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 HobbsIncluding the DAC part number. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com

Reply by ●August 11, 20152015-08-11

>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 asingle>> 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.comit says output coupling=DC and output impedance is 0.5 ohm.How can I upload image here? --------------------------------------- Posted through http://www.Electronics-Related.com

Reply by ●August 11, 20152015-08-11

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

Reply by ●August 11, 20152015-08-11

>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, capacitorsand>> >> resistors. I am generating sine wave with amplitude of 1 from DACand>> >> write a frequency sweep function in Matlab however I only get a >> >> single >> >> resonator response and I am missing the second peak. when I connect1>> >> ohm or any value less than that in parallel with DAC I am able toget>> >> 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 mysine>> >> waves to 0.02 or less. >> >> What do you guys think is causing this problem that I cannot getboth>> >> 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'llbe 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 adata>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, SydneyThis is the DAC datasheet http://www.ni.com/datasheet/pdf/en/ds-10 --------------------------------------- Posted through http://www.Electronics-Related.com

Reply by ●August 11, 20152015-08-11

>>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 Iconnect>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't0.5> >>> >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 couplingÃœ 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.comThis 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

Reply by ●August 11, 20152015-08-11

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.comA 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.

Reply by ●August 11, 20152015-08-11

>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 asingle>> resonator response and I am missing the second peak. when I connect 1ohm>> 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 resistorsin>> parallel with DAC but I changed the amplitude of my sine waves to 0.02or>> 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