The driven waveform must be sinusoidal. Purity is not critical. It can be somewhat ragged. A way to detect phase I am considering is to use comparators to convert sinewave to square wave, and then detect phase difference in the similar way the CD4046 does. The logic would have to be more complex than just an exclusive OR gate though, because the XOR adjusts phase to 90 degrees. I have trouble finding a successor to the EOL XR-2206. Suggestions would be appreciated. If I do not find one I may have to try self excitation. -- To email me directly remove sj. from my email address's domain name. This is a spam jammer.
Crystal Controlled Oscillator
Started by ●January 3, 2022
Reply by ●January 5, 20222022-01-05
Reply by ●January 5, 20222022-01-05
On 5/1/22 5:15 pm, Artist wrote:> The driven waveform must be sinusoidal. Purity is not critical. It can > be somewhat ragged. > > A way to detect phase I am considering is to use comparators to convert > sinewave to square wave, and then detect phase difference in the similar > way the CD4046 does. The logic would have to be more complex than just > an exclusive OR gate though, because the XOR adjusts phase to 90 degrees.Tried reading the datasheet? The CD4046 has two different phase comparators. You'll find this document useful: <https://www.ti.com/lit/an/scha002a/scha002a.pdf> CH
Reply by ●January 5, 20222022-01-05
On Wednesday, January 5, 2022 at 5:15:37 PM UTC+11, Artist wrote:> The driven waveform must be sinusoidal. Purity is not critical. It can > be somewhat ragged. > > A way to detect phase I am considering is to use comparators to convert > sinewave to square wave, and then detect phase difference in the similar > way the CD4046 does. The logic would have to be more complex than just > an exclusive OR gate though, because the XOR adjusts phase to 90 degrees.As Clifford Heath has pointed out, there are a variety of ways of detecting phase. The classical approach is to use a four quadrant multiplier to gerenate the product of the sine wave being looked at and the your reference sinewave. Trigometry lets you see that the product waveform has a DC content the corresponds to the phase difference between the two sine waves. You do have to filter out the alternating components. A switching detector effectively multiplies the sine wave you are looking by a square wave of the same frequency. It doesn't give quite the same result, but it close enough for most applications. Turning both sine waves into square waves before you multiply them together is even cruder, but can be good enough.> I have trouble finding a successor to the EOL XR-2206. Suggestions would be appreciated. If I do not find one I may have to try self excitation.Since we haven't got a clue what kind of voltage, current and frequency you have to deal with , we can't really give you any useful advice. There are a lot of sine wave oscillators around. Some of them can be tuned to run over a range of frequencies. I have suggested using a "modfied sine wave" to drive your transducer - it's just a three level approximation to a sine wave. It's virtue is that it doesn't have any third harmonic content, but it does have the higher odd harmonics you'd get from a square wave drive. if less of the fifth and a bit less of the seventh. -- Bill Sloman, Sydney
Reply by ●January 5, 20222022-01-05
Artist wrote:> The driven waveform must be sinusoidal. Purity is not critical. It can > be somewhat ragged. > > A way to detect phase I am considering is to use comparators to convert > sinewave to square wave, and then detect phase difference in the similar > way the CD4046 does. The logic would have to be more complex than just > an exclusive OR gate though, because the XOR adjusts phase to 90 degrees. > > I have trouble finding a successor to the EOL XR-2206. Suggestions would > be appreciated. If I do not find one I may have to try self excitation. >A filtered square wave, or (for fun) a 74HC4017 and some weighted resistors. We had a thread on that awhile back--2011, it was. The OP was George Herold. (George? You still out there, man?) <https://groups.google.com/g/sci.electronics.design/c/sZWMknd6yjw/m/8HdJPZFUriAJ> Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●January 5, 20222022-01-05
> Artist wrote: >> The driven waveform must be sinusoidal. Purity is not critical. It >> can be somewhat ragged. >> >> A way to detect phase I am considering is to use comparators to >> convert sinewave to square wave, and then detect phase difference >> in the similar way the CD4046 does. The logic would have to be more >> complex than just an exclusive OR gate though, because the XOR >> adjusts phase to 90 degrees.[...] Why does that matter? Jeroen Belleman
Reply by ●January 5, 20222022-01-05
On 1/5/22 1:01 AM, Anthony William Sloman wrote:> On Wednesday, January 5, 2022 at 5:15:37 PM UTC+11, Artist wrote: >> The driven waveform must be sinusoidal. Purity is not critical. It can >> be somewhat ragged. >> >> A way to detect phase I am considering is to use comparators to convert >> sinewave to square wave, and then detect phase difference in the similar >> way the CD4046 does. The logic would have to be more complex than just >> an exclusive OR gate though, because the XOR adjusts phase to 90 degrees. > > As Clifford Heath has pointed out, there are a variety of ways of detecting phase. > > The classical approach is to use a four quadrant multiplier to gerenate the product of the sine wave being looked at and the your reference sinewave. > > Trigometry lets you see that the product waveform has a DC content the corresponds to the phase difference between the two sine waves. You do have to filter out the alternating components. > > A switching detector effectively multiplies the sine wave you are looking by a square wave of the same frequency. It doesn't give quite the same result, but it close enough for most applications. > > Turning both sine waves into square waves before you multiply them together is even cruder, but can be good enough. > >> I have trouble finding a successor to the EOL XR-2206. Suggestions would be appreciated. If I do not find one I may have to try self excitation. > > Since we haven't got a clue what kind of voltage, current and frequency you have to deal with , we can't really give you any useful advice. > There are a lot of sine wave oscillators around. Some of them can be tuned to run over a range of frequencies. > > I have suggested using a "modfied sine wave" to drive your transducer - it's just a three level approximation to a sine wave. It's virtue is that it doesn't have any third harmonic content, but it does have the higher odd harmonics you'd get from a square wave drive. if less of the fifth and a bit less of the seventh. >The max frequency should be no lower than 80kHz, and at least 70kHz. For part count reasons I am hoping not to have to filter out that higher harmonics of a square wave to get a sine wave. The VCO output will be amplified by an OPA552, which is known by prior experience to be sufficient to drive the piezoelectric element. Since the VCO will not drive the piezoelectric element directly its voltage, and current, output limits are not important. -- To email me directly remove sj. from my email address's domain name. This is a spam jammer.
Reply by ●January 6, 20222022-01-06
My last post was not clear. Apologies The VCO I seek preferably produces a sine wave to reduce the part count required to filter out the higher harmonics of a square wave. The sine wave need not be clean. There can be some raggedness to it. It must be capable of frequencies at least within the band between 70kHz, and 80kHs. That's 70 kHz or below on the low end., and 80kHz or above on the high end. Output voltage level, and current source limits, are not important because its output will be boosted to what is needed by a following stage. -- To email me directly remove sj. from my email address's domain name. This is a spam jammer.
Reply by ●January 6, 20222022-01-06
On a sunny day (Thu, 6 Jan 2022 08:27:14 -0800) it happened Artist <sepflanze@sj.gmail.com> wrote in <sr7594$ro5$1@dont-email.me>:>My last post was not clear. Apologies > >The VCO I seek preferably produces a sine wave to reduce the part count >required to filter out the higher harmonics of a square wave. > >The sine wave need not be clean. There can be some raggedness to it. > >It must be capable of frequencies at least within the band between >70kHz, and 80kHs. That's 70 kHz or below on the low end., and 80kHz or >above on the high end. > >Output voltage level, and current source limits, are not important >because its output will be boosted to what is needed by a following stage.You will have to be more specific, but a few thoughts Those transducrs are normally capacitive, several nF, at leas the big ones I use Big ones http://panteltje.com/pub/40_KHz_ultrasonic_transducers_IMG_5133.JPG But I use small ones too http://panteltje.com/pub/44kHz_Doppler_radar_Rx_transducer_and_coil_IMG_4097.JPG the driving method differs! For a sine wave, drive it with an inductor (you can, once you know C_transdcer and frequency calculate L. opamp - L - [transducer]--- ground Now L sets the resonance. You will get very high voltage on the transducer for even a low drive that way, You can reduce Q by adding a series resistor for example. For a one stage you can take feedback from the transducer to an input and it will self oscillate (at value set by L). One way to go about it... If all you want is a sinewave between 70 kHz and 80 kHz wind a coil and use this +12 coil | |--- d ---------->| JFET | | |--- s | { === | | ( | 1 n |--------0 approx sine out | ( L |--------| | ( | | | === [ ] 470 | | 2 n | /// /// /// calculate L, wind it on some core. Note the C value ratio, could be 10 nF 20 nF etc
Reply by ●January 6, 20222022-01-06
Jan Panteltje wrote:> On a sunny day (Thu, 6 Jan 2022 08:27:14 -0800) it happened Artist > <sepflanze@sj.gmail.com> wrote in <sr7594$ro5$1@dont-email.me>: > >> My last post was not clear. Apologies >> >> The VCO I seek preferably produces a sine wave to reduce the part count >> required to filter out the higher harmonics of a square wave. >> >> The sine wave need not be clean. There can be some raggedness to it. >> >> It must be capable of frequencies at least within the band between >> 70kHz, and 80kHs. That's 70 kHz or below on the low end., and 80kHz or >> above on the high end. >> >> Output voltage level, and current source limits, are not important >> because its output will be boosted to what is needed by a following stage. > > You will have to be more specific, > but a few thoughts > Those transducrs are normally capacitive, several nF, at leas the big ones I use > Big ones > http://panteltje.com/pub/40_KHz_ultrasonic_transducers_IMG_5133.JPG > > But I use small ones too > http://panteltje.com/pub/44kHz_Doppler_radar_Rx_transducer_and_coil_IMG_4097.JPG > > the driving method differs! > > For a sine wave, drive it with an inductor (you can, once you know C_transdcer and frequency > calculate L. > > opamp - L - [transducer]--- ground > > Now L sets the resonance. > > You will get very high voltage on the transducer for even a low drive that way, > You can reduce Q by adding a series resistor for example. > For a one stage you can take feedback from the transducer to an input > and it will self oscillate (at value set by L). > One way to go about it... > > If all you want is a sinewave between 70 kHz and 80 kHz > wind a coil and use this > > +12 > coil | > |--- d > ---------->| JFET > | | |--- s > | { === | > | ( | 1 n |--------0 approx sine out > | ( L |--------| > | ( | | > | === [ ] 470 > | | 2 n | > /// /// /// > > > calculate L, wind it on some core. > Note the C value ratio, could be 10 nF 20 nF etc > >Won't work. The mechanical resonance dominates the response. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●January 6, 20222022-01-06
On 06/01/2022 16:27, Artist wrote:> My last post was not clear. Apologies > > The VCO I seek preferably produces a sine wave to reduce the part count > required to filter out the higher harmonics of a square wave. > > The sine wave need not be clean. There can be some raggedness to it. > > It must be capable of frequencies at least within the band between > 70kHz, and 80kHs. That's 70 kHz or below on the low end., and 80kHz or > above on the high end. > > Output voltage level, and current source limits, are not important > because its output will be boosted to what is needed by a following stage. >You can use the VCO in a CD4046 at (say) 8x or 16x the desired frequency into a weighted resistor "DAC" using a shift register or ring counter (I think Phil H suggested a CD4017 as one possibility). The resulting multi-stepped near sine is very easy to filter if needed. You could use either of the CD4046 phase comparators to servo the VCO frequency to resonance on the piezo current vs voltage, as others already suggested. With each passing day your project looks to be getting easier and easier! piglet
