# filters's questions - English 1answer

1.771 filters questions.

### How to set a Carrier Wave for DBPSK Modulators in gnuradio?

for a Project I need to build an Audio Modem in GNU Radio. I decided, that it would be the best to use DBPSK Modulation, because that is fast and relatively noise resistant. But as it seems, the ...

### Least Squares with Non Zero Mean Noise

1 answers, 143 views filters filter-design noise least-squares
What happens if the noise has no zero mean? I mean, if the exercise is something like: $$y(k) = A x + \eta(k)$$ When I have zero mean, I start from: $$y = A x$$ $$\Rightarrow \hat{y} = A \hat{x}$$ ...

### Why Convolution between signal and channel is not done directly in SIMO channel

0 answers, 29 views filters convolution ofdm

### -1 Edge detection for 1-D signals;sampling frequency of low pass filtering [on hold]

Could you please introduce me some references about edge detection of 1-D signals? I have a pulse similar to rectangular pulses which is immersed in noise. Would you please introduce me some filters ...

### -1 Why does filtfilt function require a negative sign?

I am trying to extract features from a signal using filtfilt function in MATLAB. I implement the filtfilt function on my original signal using a high pass filter(second derivative) and use the peak of ...

### 2 Introductory resources to mathematical properties of “dynamically recalculable” filters in audio/musical equalizers?

1 answers, 69 views filters audio reference-request
Introductory resources to mathematical properties of "dynamically recalculable" filters in audio/musical equalizers? Particularly, I want to understand What mathematical features (e.g. monotonicity ...

### How can a RLS algorithm utilise Wiener filter as FIR (M-tap) block?

I'm currently working with a dataset of $5000$ pulses of $N=15000$ samples each. I managed to implement the RLS algorithms with a FIR M-Tap filter such that $M\leq 15000$ ($150$ seems to achieve the ...

### 1 What is the difference between the sampling frequency of signal and sampling frequency of filter

I believe that there is no connection between the sampling frequency used for converting an analogue filter to digital filter and the one used to sample a signal that the filter will be used on. But I ...

### 2 How does a digital filter work?

To introduce my situation: I'm developing a digital synthesizer in a form of a C++ library, working with low level APIs like WASAPI, ASIO, ALSA etc. It's probably not very practical and I'm mostly "...

### How do I show an impulse response leads to a zero-phase frequency response?

2 answers, 59 views filters impulse-response linear-phase
I'm trying to understand how to show that with real coefficients, the phase response of a filter is 0. Here is the impulse response $h[n] = b_1d[n+1] + b_0d[n] + b_1d[n-1]$ How should I approach ...

### Filtering odd and even frequencies

1 answers, 258 views fft filters

### Realization of a filter based on its transfer function

How can we check whether the filter is realizable given its transfer function and What are the parameters the realization depends on? Here is an example: Show that a filter with transfer function ...

### 1 audio for VOIP - filter and resample or viceversa?

1 answers, 220 views filters audio sound
I am a noob to signal processing, but I need to create some audio files for IVR for Asterisk VOIP. So my lady friend with a nice voice records her message on a Windows machine and sends me a 44KHz, ...

### 8 Savitzkyâ€“Golay filter vs. IIR or FIR linear filter

A traditional IIR / FIR filter (lowpass to remove the high freq oscillations), e.g. moving average, or a Savitzky-Golay filter can all be useful to smoothen a signal, such as an envelope signal: ...

### 1 Filter, window function and audio signal: how to link them to each other?

1 answers, 263 views filters window-functions
I have a question about the implementation of digital filters in CoreAudio. I'm in big trouble because it is a few weeks I'm trying to understand how to implement them. The basic idea is this: while I ...

### Removing high pitch noise embedded in audio spectrum

1 answers, 402 views filters noise noise-cancellation
I have an audio clip. Here is the clip in wave format https://www.dropbox.com/s/542jgpfk7bfkt01/sample.wav?dl=0 I chose the following area of time domain signal The spectrum of this signal shows ...

### 3 How to find the group delay of IIR filters in Python/SciPy

I sent a square wave signal (red) through a IIR filter (butterworth in this case), to make it more "realistic". Then there's a slight group delay in my output signal (blue). Is there a way to find out ...

### Is Kelly Lochbaum Ladder Filter LTI?

I am a bit confused about the Kelly Lochbaum Ladder Filter. Image below taken from here. My question is, is this an LTI (linear time-invariant) filter? I thought that it was LTI, but I am not sure ...

### 1 4-phase FIR LPF in MATLAB

I'm trying to create a low pass FIR filter using the coefficients I found in ITU 1770-3 on page 18. This is the last piece of the puzzle for an audio loudness metering algorithm I'm working on. I'm ...

### 2 Sliding window minimum and maximum filter in MATLAB

2 answers, 4.514 views filters matlab
I'm trying to apply a sliding window minimum and maximum filter to an image of a certain window size. Actually, I'm trying to find the optimum window size for it. But I really haven't gotten the hang ...