Retired, worked at MIT Lincoln Laboratory 1961-2020. Involved in digital signal processing, speech, satellite reliability and quantum computing.

Re: Single vs split Hilberts

Reply posted 2 weeks ago (06/29/2020)
Joe, I may be beating my own drum here, but I do have some thoughts to share.First, if an input x(n) is fed into two causal time invariant linear systems, H_1(z)...
I think you have to express your requirement more carefully. What exactly is a precise delay filter? If the input and the output of the filter have the same sampling...
The ringing you refer to is because your approach creates a filter frequency response which has a discontinuity. I'm using the word discontinuity incorrectly because...
In any modulation system for which the constellation of possible signals, if there are several constellation members with the same angle but different amplitudes...
Westrace, perhaps I am guilty of requiring you to be too precise, but usually the matched filter is used to identify a signal buried in noise. Unless the noise is...

Re: Auto-Correlation based Carrier Frequency Recovery

Reply posted 1 month ago (05/31/2020)
I need some clarification.   At the receiver you have some signal x[n] that you want and another signal y[n] which is a pure sinusoid. y[n] is unwanted. You only...

Re: Digital Filters that have prescribed phase shift

Reply posted 1 month ago (05/30/2020)
The 90 degree FIR half-band filter, zeroes rotated by ninety degrees, gives you an FIR Hilbert transformer approximation, phase a perfect 90 degrees, but it is not...

Re: Digital Filters that have prescribed phase shift

Reply posted 1 month ago (05/30/2020)
Thanks, that seems to work.

Re: Digital Filters that have prescribed phase shift

Reply posted 1 month ago (05/30/2020)
gretzteam, I haven't seen it before, but it gives a specific case, which I would call N=9. It's a 90 degree case. There's a set of formulas for the 90 degree case...

Re: Digital Filters that have prescribed phase shift

Reply posted 1 month ago (05/30/2020)
It's a pdf file. It's a plot made by GNU octave, which is a MATLAB equivalent system that's free.

Re: Digital Filters that have prescribed phase shift

Reply posted 1 month ago (05/30/2020)
I did try that. It let me choose a file, which I did. But apparently there is some other step because the file I chose didn't seem to show up.   Using drop and...

Re: Digital Filters that have prescribed phase shift

Reply posted 1 month ago (05/30/2020)
Thanks emeb.  Is it common knowledge how to design such filters?  I am using a mapping based on Jacobian elliptic functions and the resulting designs are provably...
Almost sixty years ago I needed an all-pass recursive digital filter with two outputs, such that the phase difference between the outputs was a very good approximation...

Re: LTE IFFT Sampling and Nyquist Rate

Reply posted 2 months ago (05/14/2020)
Zack, I'm not familiar with the application and didn't even know what the initials LTE stood for. (Side comment - the first time you use a a letter sequence abbreviation,...

Re: PhD in E.E. is it really worth it

Reply posted 2 months ago (05/08/2020)
I began working after getting my Masters degree in 1961, with the idea that I would work for a few years and then get a PhD. I knew I wanted to do research. But...
I don't know if it is as simple as this. If a waveform has the componentx(nT) = Aexp(j n omega T) then the product of the sample with its predecessor's complex conjugate...

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