Thread Subject: RECTWIN function

I am totally new to DSP matlab :)

1. How to use RECTWIN function in matlab, suppose if i have signal of 127 by1 and -70 to +70 Hz but i am only interested in -30 to +30 (64 samples),,,,,,,,actually i ws just plaaying around i convolve some uniformly sampled spikes with a sinusoid..result is 127 by 1 vector ,in frequency spectra now i need my sinusoid back so how can i use box car for this

2. similarly in time domain how can i use sinc for this

3. what exactly we mean by oversampling, suppose i had done sampling of signal which means i have some number of samples say 54 at a sampling rate of 100Hz i:e .01 sec. Now when i read about oversampling it says increasing the Bandwidth by 2B, by increasing number of samples (N=2*M..Number of samples in frequency domain). But my value of samples will still be 54, how i done over sampling, i mean i dont have 108 Fourier Coffecients or Amplitude value with me then how can i take summation over 108 coffecients.

 

4.Is that mean we can only do oversampling when we know our analog signal.....

5. Where i can find good tutorial about over sampling

Here tutoriasl about oversampling:


1) http://en.wikipedia.org/wiki/Oversampling

2) http://en.wikipedia.org/wiki/Oversampling_and_undersampling_in_data_analysis

3) http://www.answers.com/topic/oversampling

4) What is oversampling in DSP(Digital Signal Processing):

http://ask.reference.com/web?q=Oversampling&l=dir&qsrc=2893&o=10603

Here's a short and good explanation what does oversampling with a matlab program (example of oversampling):

http://www.scribd.com/doc/7043378/Matlab-Programs

Best wishes,

Michael