| Author |
Message |
lau er kheng
Joined: 27 Sep 2004
Posts: 3
|
 28 Sep 2004 8:07 how to generate a high frequency? |
|
|
|
|
can anyone tell me how to generate a high frequency from the range 1MHz until minimun of 1GHZ by using the signal genrator or function generator???
if possible,can show me the schematic or the circuit diagram??
|
|
| Back to top |
|
 |
bobcat1
Joined: 10 Jul 2002
Posts: 1119
Helped: 48
|
29 Sep 2004 22:03 Re: how to generate a high frequency? |
|
|
|
|
Hi use the AD9850 DDS chip from analog it can work up to 100M and the multiply it using PLL
Look at www.analog.com for DDS there are some app note also search google for AD9850 you will find many circuit describe how to use it
regards
bobi
|
|
| Back to top |
|
|
Borber
Joined: 01 Jan 1970
Posts: 1561
Helped: 117
Location: Slovenia
|
29 Sep 2004 22:25 Re: how to generate a high frequency? |
|
|
|
|
One of the possibilities is to make 1GHz to 2GHz VCO and fixed oscillator at 1GHz. Mix both signals and filter the resulting signal. You wil get 0 to 1GHz signal generator.
Second possibility is to build number of VCO's to cover entire wanted frequency band.
|
|
| Back to top |
|
|
Google
AdSense
|
29 Sep 2004 22:25 Ads |
|
|
|
|
|
|
| Back to top |
|
|
flatulent
Joined: 19 Jul 2002
Posts: 4879
Helped: 324
Location: Middle Earth
|
29 Sep 2004 22:59 Re: how to generate a high frequency? |
|
|
|
|
| Another option if you do not need specific frequencies is to first generate an octave range of them and then use binary counters to get the lower frequencies.
|
|
| Back to top |
|
|
eltonjohn
Joined: 22 Feb 2002
Posts: 1751
Helped: 28
|
29 Sep 2004 23:31 Re: how to generate a high frequency? |
|
|
|
|
Hi ..what borber suggests is probably the best way to go .. the higher the VCO frequency the wider the frequency interval . Some time ago i used SIRENZA's VCO793-1500T . that does 1G to 2Ghz.Now you just need a 1Ghz oscilator and a mixer .
you could use the same vco and control both with a DAC and a processor
the output frequency of the mixer amplified and filtered could then be fed to a prescaler and the frequency mesured to adjust the control DACS
Ahhh. i just got a new computer and i can't find the part number for the mixer .. well take a look at SIRENSA's web site .. THEY HAVE IT ALL
http://www.sirenza.com/products_summary.asp?family=Signal%20Source&line=VCO&series=793%20Series&menu=signalsource
see here for mixers :
http://www.sirenza.com/products_summary.asp?family=All%20Products&menu=allproducts
|
|
| Back to top |
|
|
lau er kheng
Joined: 27 Sep 2004
Posts: 3
|
30 Sep 2004 6:41 Re: DDS? |
|
|
|
|
can i know wat's the purpose for the DDS??will it generate a frequency? and anyone who got the schematic diagram for the very high frequency signal generator?(from 1MHz until 1GHz)!
and can i use which type of VCO and the oscillator to generate such high frequency?
|
|
| Back to top |
|
|
djalli
Joined: 10 Nov 2001
Posts: 887
Helped: 15
Location: 1600 Pennsylvania Avenue, Washington DC 20500
|
30 Sep 2004 6:59 how to generate a high frequency? |
|
|
|
|
Below 100MHz range it can be a simple circuit, that is true.
lau er kheng I do not think you can make an "as easy" circuit for an oscillator for the range 100MHz to 1GHz.
There are issues (which can be yours too) to consider, it is not easy!
You need a particular RF transistor first of all. RF-- BJT, FET, MESFET, MOSFET etc. are particular for this purpose.
Where are you leading, how do you want it? In what range loss,gains etc???
Please state your problem much clear.
djalli
|
|
| Back to top |
|
|
