XO controlled 480Hz Oscillator
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From: Vladimir Vassilevsky on 3 Feb 2010 09:03 Uwe Hercksen wrote: > > > Vladimir Vassilevsky schrieb: > >> The simplest way is MCU with external crystal. For 480 Hz output, the >> crystal is likely to be a multiple of 3 MHz. The 12.0 MHz would be the >> most common. > > > Hello, > > but for 480 Hz out of 12 MHz, the divider is 25. If a square wave is > necessary, better use a 24 MHz crystal and divide two times by five and > then by two. ???? For 480 Hz square wave out of 12 MHz, the divider is 12500. 2 x 2 x 5 x 5 x 5 x 5 x 5 Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
From: George Herold on 3 Feb 2010 09:15 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.
From: MooseFET on 3 Feb 2010 09:18 On Feb 2, 9:46 pm, ehsjr <eh...(a)nospamverizon.net> wrote: [..3.29136MHz..] > divide it by 8192 you'll get the 480 Hz you want. > The 4060 has an 8192 ouput on Q13. I suggest the HC4060 not the CD4060. The HC has a smaller delay so making a good oscillator a 3.29136MHz is easier with it. Follow the app notes
From: MooseFET on 3 Feb 2010 09:20 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
From: Vladimir Vassilevsky on 3 Feb 2010 09:57
George Herold 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? > OK this is probably a stupid idea. But could you phase lock to the > 8th harmonic of the 60Hz line frequency? Connect to AC, 3 full wave rectifiers in series, then comparator. Adjust DC bias at each rectifier for 50/50 duty circle? Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com |