XO controlled 480Hz Oscillator
in [Design]
|
Prev: The UT804 bench multimeter
Next: Small genset
From: Bill Sloman on 4 Feb 2010 17:14 On Feb 4, 4:43 am, George Herold <ggher...(a)gmail.com> wrote: > On Feb 3, 10:05 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- > > > > Web-Site.com> wrote: > > On Wed, 3 Feb 2010 06:15:37 -0800 (PST), George Herold > > > <ggher...(a)gmail.com> wrote: > > >On Feb 2, 11:29 am, Chris <christopher.man...(a)gmail.com> wrote: > > >> What is the simplest way to get 480Hz from a crystal controlled > > >> oscillator? Looks like most of the pre-packaged XO's and VCXO, seem > > >> to put out much higher frequencies. Would a series of dividers be the > > >> best way? > > > >> Thanks, > > >> Chris KQ6UP > > > >OK this is probably a stupid idea. But could you phase lock to the > > >8th harmonic of the 60Hz line frequency? > > > >George H. > > > AC Line is sort of sinusoidal, so 8th harmonic content is probably not > > all that wonderful, but a PLL with a DIV8 as feedback should work > > great... do it all in cheapy CMOS, at low power ;-) > > > ...Jim Thompson > > -- > > | James E.Thompson, CTO | mens | > > | Analog Innovations, Inc. | et | > > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > > | Phoenix, Arizona 85048 Skype: Contacts Only | | > > | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | > > | E-mail Icon athttp://www.analog-innovations.com| 1962 | > > > I love to cook with wine. Sometimes I even put it in the food. > > Yeah, that's what I meant. I've never done a PLL circuit.... But if I > can 'restrict' the VCO so that it only 'goes' near 480 Hz, then it > should be a simple matter to 'lock-in'. Unfortunately, while the mains frequency it held at precisely 50Hz (or 60Hz) over the long term, it can vary by a few percent in the short term, so it wouldn't be a good idea for Chris to lock his 480Hz to the mains. -- Bill Sloman, Nijmegen
From: Spehro Pefhany on 4 Feb 2010 19:39 On Wed, 3 Feb 2010 06:20:28 -0800 (PST), the renowned MooseFET <kensmith(a)rahul.net> wrote: >On Feb 3, 4:49�am, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> >wrote: >> On Tue, 2 Feb 2010 08:29:47 -0800 (PST), the renowned Chris >> >> <christopher.man...(a)gmail.com> wrote: >> >What is the simplest way to get 480Hz from a crystal controlled >> >oscillator? �Looks like most of the pre-packaged XO's and VCXO, seem >> >to put out much higher frequencies. �Would a series of dividers be the >> >best way? >> >> >Thanks, >> >Chris KQ6UP >> >> I'd suggest a PIC12F508 and a standard 3.6864MHz crystal (eg. Citizen >> HC49US-3.6864MABJ-UB) which total less than $2 one-off. � >> >> To get exact 50% duty cycle 480Hz square waves you need exactly 960 >> instruction cycles between toggles during which time you can count >> down from 255 a few times, count down from something less than 255 >> once, and yank the leash of the WDT, and loop back. Easily done >> in a handful of lines of assembler. > >With a HC4060 you need fewer instructions Not that many fewer. 16 words of program memory and one RAM location. http://www.speff.com/pic_480.jpg http://www.speff.com/freq_480.jpg The load caps are not optimal because it's in a solderless breadboard, but still the accuracy is within about 0.004%. Not too shabby. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: Chris on 4 Feb 2010 20:23 On Feb 4, 4:39 pm, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Wed, 3 Feb 2010 06:20:28 -0800 (PST), the renowned MooseFET > > > > <kensm...(a)rahul.net> wrote: > >On Feb 3, 4:49 am, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> > >wrote: > >> On Tue, 2 Feb 2010 08:29:47 -0800 (PST), the renowned Chris > > >> <christopher.man...(a)gmail.com> wrote: > >> >What is the simplest way to get480Hzfrom a crystal controlled > >> >oscillator? Looks like most of the pre-packaged XO's and VCXO, seem > >> >to put out much higher frequencies. Would a series of dividers be the > >> >best way? > > >> >Thanks, > >> >Chris KQ6UP > > >> I'd suggest a PIC12F508 and a standard 3.6864MHz crystal (eg. Citizen > >> HC49US-3.6864MABJ-UB) which total less than $2 one-off. > > >> To get exact 50% duty cycle480Hzsquare waves you need exactly 960 > >> instruction cycles between toggles during which time you can count > >> down from 255 a few times, count down from something less than 255 > >> once, and yank the leash of the WDT, and loop back. Easily done > >> in a handful of lines of assembler. > > >With a HC4060 you need fewer instructions > > Not that many fewer. 16 words of program memory and one RAM location. > > http://www.speff.com/pic_480.jpghttp://www.speff.com/freq_480.jpg > > The load caps are not optimal because it's in a solderless breadboard, > but still the accuracy is within about 0.004%. Not too shabby. > > Best regards, > Spehro Pefhany > -- > "it's the network..." "The Journey is the reward" > sp...(a)interlog.com Info for manufacturers:http://www.trexon.com > Embedded software/hardware/analog Info for designers: http://www.speff.com That is really nice. I strayed away from this one because I have never programed a PIC before. I was also wondering about caveats of using a proto board before I solder the final product. I am getting 25 CD4060B's to play with so I would have to worry about screwing up. I will probably get a socket for the crystal. I am anxious about getting my parts in the mail. I am anxious to see if my solution fixes my fullcoat deck. It all looks good on paper, but the proof is in the pudding. Regards, Chris Maness
From: Ross Herbert on 4 Feb 2010 22:00 On Tue, 2 Feb 2010 08:29:47 -0800 (PST), Chris <christopher.maness(a)gmail.com> wrote: :What is the simplest way to get 480Hz from a crystal controlled :oscillator? Looks like most of the pre-packaged XO's and VCXO, seem :to put out much higher frequencies. Would a series of dividers be the :best way? : :Thanks, :Chris KQ6UP You might be able to still pick up this surplus item http://surplussalespa.com/catalog/product_info.php?products_id=7474 With a bit of trimming I'm sure it could be pulled to 3.360kHz and then you can use a divide by 7 counter using the HCF4018 to get 480Hz. http://www.jaycar.com.au/images_uploaded/CD4018B.PDF
From: George Herold on 4 Feb 2010 22:30
On Feb 4, 5:14 pm, Bill Sloman <bill.slo...(a)ieee.org> wrote: > On Feb 4, 4:43 am, George Herold <ggher...(a)gmail.com> wrote: > > > > > > > On Feb 3, 10:05 am, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- > > > Web-Site.com> wrote: > > > On Wed, 3 Feb 2010 06:15:37 -0800 (PST), George Herold > > > > <ggher...(a)gmail.com> wrote: > > > >On Feb 2, 11:29 am, Chris <christopher.man...(a)gmail.com> wrote: > > > >> What is the simplest way to get 480Hz from a crystal controlled > > > >> oscillator? Looks like most of the pre-packaged XO's and VCXO, seem > > > >> to put out much higher frequencies. Would a series of dividers be the > > > >> best way? > > > > >> Thanks, > > > >> Chris KQ6UP > > > > >OK this is probably a stupid idea. But could you phase lock to the > > > >8th harmonic of the 60Hz line frequency? > > > > >George H. > > > > AC Line is sort of sinusoidal, so 8th harmonic content is probably not > > > all that wonderful, but a PLL with a DIV8 as feedback should work > > > great... do it all in cheapy CMOS, at low power ;-) > > > > ...Jim Thompson > > > -- > > > | James E.Thompson, CTO | mens | > > > | Analog Innovations, Inc. | et | > > > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > > > | Phoenix, Arizona 85048 Skype: Contacts Only | | > > > | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | > > > | E-mail Icon athttp://www.analog-innovations.com| 1962 | > > > > I love to cook with wine. Sometimes I even put it in the food.. > > > Yeah, that's what I meant. I've never done a PLL circuit.... But if I > > can 'restrict' the VCO so that it only 'goes' near 480 Hz, then it > > should be a simple matter to 'lock-in'. > > Unfortunately, while the mains frequency it held at precisely 50Hz (or > 60Hz) over the long term, it can vary by a few percent in the short > term, so it wouldn't be a good idea for Chris to lock his 480Hz to the > mains. > > -- > Bill Sloman, Nijmegen- Hide quoted text - > > - Show quoted text - Hmm I've never looked that closely at line frequency. Do you have any idea how long you'd have to average for to 'clean things up'? A few second time constant is not too bad for an oscillator. George H. |