Cancelling noise in acoustic signals

Started by Atri Mandal in comp.dsp15 years ago 6 replies

Hi, I am detecting a 4 KHz acoustic signal in the presence of noise at a sampling rate of 44.1 KHz. Since I'm synchronizing with the start of...

Hi, I am detecting a 4 KHz acoustic signal in the presence of noise at a sampling rate of 44.1 KHz. Since I'm synchronizing with the start of the signal I have to detect the frequency as soon as I receive it which means I'll have to take a decision about the presence or absence of the signal on the basis of a very few samples. I'm using Goertzel(a kind of DFT) for this purpose and it is pret...


Burst tone detection of unknown frequency

Started by Jay Fenton in comp.dsp12 years ago 16 replies

Hi, I've been trying to find the most optimal algorithm to detect a sustained burst of tone at an unknown (but higher than speech)...

Hi, I've been trying to find the most optimal algorithm to detect a sustained burst of tone at an unknown (but higher than speech) frequency in realtime, for use in voicemail detection (think long beep). I don't have much experience in the signal processing realms, and would appreciate any appropriate pointers. Am I right in thinking that Goertzel is only suited to the detection of ...


fft frequency and phase resolution.

Started by Anonymous in comp.dsp4 years ago 7 replies

hey guys, This should be a simple questions for the pros here, in an ideal situation a noise free sinusoid of 2V amplitude and 2 degree @ 10MHz...

hey guys, This should be a simple questions for the pros here, in an ideal situation a noise free sinusoid of 2V amplitude and 2 degree @ 10MHz is sampled at 50MSa/sec. I use the Goertzel algorithm to find the magnitude and phase of this 10MHz from 500 samples, what is the maximum precision of the magnitude and phase calculated using this method i.e. how close will magnitude and pha


Experience with the Sliding DFT, anyone?

Started by hxtasy in comp.dsp11 years ago 7 replies

Hello I would like to know if anyone has experience with the sliding DFT algorithm. It is somewhat similar to the Goertzel algorithm. All I...

Hello I would like to know if anyone has experience with the sliding DFT algorithm. It is somewhat similar to the Goertzel algorithm. All I would like to know is what application this algorithm would be useful in? I cannot find that much information on the internet and have not had time to look into any books about the sliding DFT. So if anyone could mention the mathematics behind it the ...


Normalizing the magnitude of Goertzel Filter c#

Started by axcelenator in comp.dsp4 years ago

I'm trying to detect some frequencies of 18Khz with sample rate of 44100 [samples/sec]. When I pass a buffer(~4500 samples) to the algorithm it...

I'm trying to detect some frequencies of 18Khz with sample rate of 44100 [samples/sec]. When I pass a buffer(~4500 samples) to the algorithm it returns a magnitude in a very strange range. Sometimes i get 0.1, or 7 or 250(!) or 154 or 25000 - very strange. I can't decide on a threshold boundary for the filter. Is there any way noramlizing that result? (My result is the magnitude of the complex ...


Signal Matching

Started by amcneilly in comp.dsp10 years ago 13 replies

I am new to DSP and i have the following problem I need to detect a 20khz pulse for a sonic ranging application using a PC. I can detect...

I am new to DSP and i have the following problem I need to detect a 20khz pulse for a sonic ranging application using a PC. I can detect reasonably well the 20khz signal by measuring the RMS of the signal from the microphone then filtering the input using a high pass filter or goertzel calculation and take a RMS calculation of the filtered signal. If the RMS is over a threshold value then t...


DTMF detection through Sound Card

Started by dkurman in comp.dsp14 years ago 4 replies

Hi. I have posted two messages, but I can?t get this working. I mean, I'm getting the buffer from the sound card, and then I perform the...

Hi. I have posted two messages, but I can?t get this working. I mean, I'm getting the buffer from the sound card, and then I perform the goertzel algorithm with this, but the data I get is wrong almost all times. The steps are: Data: Buffer Size: 4096 Kb, N=4096, Sample Rate = 22050, Format: 16 bits 1) When I get the buffer completely filled, I read the buffer (two bytes a time) convertin...


Fax/modem detection

Started by Jadran in comp.dsp10 years ago 9 replies

Hello, I m implementing fax/modem detection. So far it is based on CNG and CED tones. Goertzel's algorithm is used for tones detections and...

Hello, I m implementing fax/modem detection. So far it is based on CNG and CED tones. Goertzel's algorithm is used for tones detections and seems to work fine. However I would like to increase reliability, specialy for cases when such tones are not present or missed. Idea is to do it by detecting presence of V.21 FSK sequence. This could be done with solution based on FSK demodulator. But as my...


Continuous Dial Tone Detection (java)

Started by Elliot in comp.dsp13 years ago

I have been asked to write an algorithm in Java to detect a continuous dial tone. Anyone have experience doing so? I have looked into the...

I have been asked to write an algorithm in Java to detect a continuous dial tone. Anyone have experience doing so? I have looked into the Goertzel algorithm, but I am unable to understand how I determine if I've encountered a dial tone by looking at the algorithm's output. For example: Sampling Rate = 8000 N = 205 Frequency = 941 k = 24 and coeff = 1.4828667 Relative magnitud...


spandsp tone_detect.c goertzel perodogram

Started by Kamanashis in comp.dsp12 years ago 3 replies

Hi, Let me explain the situation, I am trying to differ beep from different answering machine. The information about the answering machine...

Hi, Let me explain the situation, I am trying to differ beep from different answering machine. The information about the answering machine beep frequency is given below. [T-Mobile] frequency=1250 ; frequency in Hz energy=-30 ; energy in db duration=250 ; duration in milisecond [Verizon] frequency=1500 ; frequency in Hz energy=-20 ; energy in db duration=550 ; duration in milise...