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Title: cheap PLL or DDS or else Post by: Jeckson on December 19, 2009, 04:15:08 16:15 Hai
I'm looking low cost PLL or DDS or else(flexible oscillator controlled) which controlled with MCUs or PC. working in VHF range... Someone have info's where's to find low cost that kind ICs... Thank's Jeckson Title: Re: cheap PLL or DDS or else Post by: LabVIEWguru on December 20, 2009, 04:23:53 04:23 Analog Devices website has much DDS data in PDF format. Most of the DDS devices can be used in either serial (SPI) or parallel interfaces. Several of their DDS devices work in the 300 Mhz+ range. They also have application notes on designing output filters and amplifiers. I don't know what country you are in, but if you have an Analog Devices representative in your country they will probably sample you the device you need. You'll also need an oscillator to drive the DDS. It probably would be easier & less cost to build an oscillator for near the frequency you need then mix it with the DDS output. Also in the magazine section here in "QEX" there are a number of DDS construction articles.
Title: Re: cheap PLL or DDS or else Post by: nawab on December 20, 2009, 08:56:36 08:56 Look out for Silicon Labs Si 570 series progrmmable clock chips. Cypress also has similar stuff.
Title: Re: cheap PLL or DDS or else Post by: Jeckson on December 20, 2009, 01:44:11 13:44 Hai
Thank's for response.. I knew that there's some DDS from Analog and Si 570... But still cost...they around 10US$ each. Meanwhile I'm looking in 1-3 US$/pieces with Xty(10 to 99) quantities. Thank you Jeckson Title: Re: cheap PLL or DDS or else Post by: Alienbeing on December 22, 2009, 03:27:23 03:27 I have been using a DDS Kit from here. Works good from 1 to 70 mhz.
http://www.amqrp.org/kits/dds60/ Very nice quality DDS kit. I have interfaced this kit with a PIC and added an encoder and keypad for frequency selection, and LCD display to show the output frequency. I have also written a Delphi application that is interfaced through a USB to rs232 FTDI IC that allows me to control the frequency output to the DDS with my laptop with gives the best accuracy. Reason for better accuracy is the ability of the PC to perform better floating point math operations when calculating the control codes for the DDS. You will not be disappointed with this module (kit) I have bought 3 of them already. Title: Re: cheap PLL or DDS or else Post by: lab on December 22, 2009, 09:21:01 09:21 this is my controller DDS developed Poton PicBasic. I hope you can interest.
Ciao Francesco lab Title: Re: cheap PLL or DDS or else Post by: LabVIEWguru on December 23, 2009, 06:27:20 06:27 I was just thinking - some of the 1st DDS used an EPROM with a sine/cosine table programmed into it. I'm sure you changed the step size & speed. You have to research this and find the magazines the articles are in.
Title: Re: cheap PLL or DDS or else Post by: Jeckson on December 28, 2009, 02:35:57 14:35 Hai
Thank you very much >this is my controller DDS developed Poton PicBasic. I hope you can interest. >Ciao Francesco Where's the schematic picture...DSN works with another program(Is that with Workbench?),Have very old workbench and protel and seems didn't work with PIC18F452. Also here's the download time very long....Kindly with schematics picture. >I was just thinking - some of the 1st DDS used an EPROM with a sine/cosine table programmed into it. I'm sure you changed the step >size & speed. You have to research this and find the magazines the articles are in. We have similiar thought...Yes something like parts that available here. Like PLL 4046,EPROM,etc. my problem at red circle... Title: Re: cheap PLL or DDS or else Post by: bobcat1 on February 20, 2010, 01:42:09 13:42 Hi
Elektor electronics have an article on DDS using an FPGA last year - Dont remember the month On there site there is a VHDl code for the FPGA Down load the code and implement it on an ACTEL low cost (sub 1$) FPGA to get into the VHF rang Actel FPGA can work up to 300MHz to keep it low cost use a R2R and an opamp as an D2A solution You cam also implement an oscillator using an inverter and a resistor on the FPGA All the best Bobi Title: Re: cheap PLL or DDS or else Post by: marianqt on February 21, 2010, 04:56:46 16:56 Look here: http://www.rfcandy.biz/shop/ search for LMX2306,LMX2330 or LMX2322 in his site. These are great circuits for RF-PLL and are very cheap.
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