Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: How can i convert square wave to sinewave of same frequency?
Unread postPosted: Sun Mar 20, 2005 2:20 am
Anybody can help me to design a circuit to convert square wave to sine wave of same frequency to build local oscillator for radio card.
Unread postPosted: Sun Mar 20, 2005 9:40 am
If you perform a Fourier Series of a square wave you will see that it is made up of multiple frequencies, in particular, high frequency components. Therfore, to convert a square wave to a sine wave, you simply filter out the higher order components by using a low pass filter that will pass the frequency of the square wave (1/period) and reject the higher order components.
Post subject: need the same help as u need
Unread postPosted: Tue Apr 12, 2005 4:13 am
If u get pls forward to firstname.lastname@example.org..thanks..and pls
Post subject: Square to Sine for LO
Unread postPosted: Mon Apr 18, 2005 10:07 pm
Actually, most of the time you want your mixer to act as a switch, rather than as a linear multiplier. This is the reason for running standard diode double balanced mixers at the rated power (+7/17/27dBm) - to get good switching action. This gives you better 3rd order intercept performance, for example.
What frequency range are you looking at? A low pass filter only works if you have somewhat less than a 3:1 frequency range. People have used tunable bandpass filters (such as those made by Pole-Zero Corp) to cover wider ranges.