**Idea of high or low frequency for digital signal**What is the meaning of high or low frequency for digital signal.( I
think this is not related to sampling frequency right?)
For example, we have an array and its size is 10. How can I understand
whether that 10 numbers represent high or low frequency?
Thanks.
On Mon, 24 Aug 2009 13:43:58 -0700, rotor cli wrote:
> What is the meaning of high or low frequency for digital signal.( I
> think this is not related to sampling frequency right?)
>
> For example, we have an array and its size is 10. How can I understand
> whether that 10 numbers represent high or low frequency? Thanks...

**generation a narrow band signal in low frequencies**hello every body,
i'm trying to generate a narrow band signal centered in the
low frequency (around 200Hz) but it's not a noise. It likely
a sine or a sum of sines. Could some one help me ?
Oussema Lengliz wrote:
> hello every body,
>
> i'm trying to generate a narrow band signal centered in the
> low frequency (around 200Hz) but it's not a noise. It likely
> a sine or a sum of sines. Could some one help me ?
I don't understand your question... How about random noise and a
bandpass filter? Or simply add a number of sines with random frequency
and phas...

**How to measure duty cycle of very low frequency digital signal?**Hiii, All
I want to measure the duty cycle of the digital signal which hasminimal frequency at a time, i have tried through the express vi Timing and Transition measurments which measures the duty cycle, but it has the limitation that it is giving an error for the signal with the frequency lower than 17hz, so how should i measure the duty cycle of this signal? please suggest me something.
Thanks in advance,
Nishant Desai
...

**Why am I getting very high values for the very low frequency region of a random signal?**I am tyring to produce a power spectrum graph for a Tachogram data,
related to Heart Rate Variability Analysis. This data can be thought
to be as a random signal, but has a frequency spectrum range of 0 -
1HZ.
The problem that I am facing is, I am getting very high values for
very low frequency region, closer to DC value. Even the DC value is
really high, in the range 10^8. It is suppose to be a low number. Any
suggestions would be appreciated.
Thanks.
What is your sample rate, how long is your measurement time and what
window are you using? These are just few questions that would need
answe...

**signal with high- and low-frequency components, real-time application**Hi all,
I have a signal that consists of components with higher an lower
frequencies.
For my application I try to keep the higher frequencies and remove the
lower ones. Normally I could achieve this with a high-pass filter, but
in my case, the result is not promising.
Problem is, that I need the result in real-time, so for a newly read
sensor value I have to obtain the *LAST* filtered value without any
delay. A high-pass filter (or any filters I'm aware of), has it's
weaknesses on the borders of the signal (so the first and last values
of the signal are destorted through missing valu...

**Can I measure Low frequency (0-100Hz) signals trough the PC...**Can I measure Low frequency (0-100Hz) signals trough the PC audio
input by hardware modulation (eg 10 KHz) and software demodulation?
How?
Has anyone yet done this?
Any help is welcome for the Hardware (AM or FM) modulation (circuitry)
and for the software (AM or FM) demodulation (examples)
Greetings!
As I understand it, you're trying to get around the low frequency
limitation of the soundcard by using some sort of voltage to frequency
conversion. (An alternative to this is with a chopper, used to create
a pulse-width modulated stream) Both are possible to decode qu...

**FPGA CRIO LabView**I'm programming LabView 8.2/RealTime 8.2 on a CRIO-9002 equipt with a 9102 chassis. I have a some 4-20mA modules, +-10v modules and last but MOST IMPORTANTLY a 9233 +-5v module.
I've programmed the FPGA and realtime and have been able to acquire and scale appropriatly for all modules except the 9233. The 9233 is hooked up to a VibraMetrics 7002 accerlometer. (<a href="http://www.vibrametrics.com/downloads/specsheets/Model%207002.pdf" target="_blank">http://www.vibrametrics.com/downloads/specsheets/Model%207002.pdf</a>)
When&...

**The problem if one has low frequencies and high frequencies**I ask the people who my to help in my work very soon
Steps of work:
1st stage: to generate 3 signals:x1, x2, x3 and interpolated in a
vector X.
2nd stage: observed X in a window length N and plot the FFT of X
3rd stage: problem how observed X in under window of width L for
example L=N/8 and in the case of overlapping (X [ L/2:3*L/2 ]).
program :
N=512; L=N/8;
fe=3600;
t=0:1/fe:0.01;
x1=5*cos(2*pi*1000*t);
x2=5*cos(2*pi*1000*t)+10*cos(2*pi*1500*t);
x3=10*cos(2*pi*1500*t);
x=[x1 x2 x3];
y=fft(x,N);
problem L ???? XL=x(1 :L) ;
f=(1:N)*fe/N;
subplot(311);plot(x); legend('Signal x...

**Signal frequency is out of range**Have a new TFT monitor.
When my PC starts up I see a "no timing" window
(and the motherboard logo is half off the screen)
this followed by a window displaying:
----------------------------------------------
Signal frequency is out of range
H37.6kHz V50.00Hz
Please change timing signal
---------------------------------------------
As soon as windows xp starts this
disappears. And H37.6kHz V50.00Hz
becomes H64.0kHz V60.0Hz
If I uninstall the graphic drivers this
window persists.
If I resinstall the drivers then I am
back where I started.
Any ideas? I tried the monitor auto setup...

**Separating signal energy from frequency bands of an EEG Signal**Hi,
I need to extract the energy of an EEG signal within different frequency bands.I m using wavelet transform .Any body please provide me with a code.
...

**Signal frequency is out of range**Have a new TFT monitor.
When my PC starts up I see a "no timing" window
(and the motherboard logo is half off the screen)
this followed by a window displaying:
----------------------------------------------
Signal frequency is out of range
H37.6kHz V50.00Hz
Please change timing signal
---------------------------------------------
As soon as windows xp starts this
disappears. And H37.6kHz V50.00Hz
becomes H64.0kHz V60.0Hz
If I uninstall the graphic drivers this
window persists.
If I resinstall the drivers then I am
back where I started.
Any ideas? I tried the monitor auto setup...

**frequency of a signal**Sirs,
I am trying to understand how a signal would be classified as having high
or low frequency components. Let me take an example to explain.
assume
...

**frequency of signals**In general, an input signal may have any frequency component. We can observe the frequency component (entirely or partially) even the frequency of the signal is located at a fractional value of k? may i have an explaination on why such frequencies can be seen?
any help pls?
...

**Restoring signal...**Hi All!
I has a probe with non linear characteristic. The signal from this probe digitized with sample frequency Fs. So I has time series: Volts vs time. I also has calibration table which consist of 3 columns: Frequency in Hz, Amplitude in Physical_Unit/Volt and phase in degree. Can I restore signal in Physical_Units?
For example: Fs=128 Hz
Calibration table is:
0.0001 50002.50013 88.99
0.001 5000.250013 88.9
0.01 500.0250013 88.8
0.05 100.010001 88.7
0.1 50.00750113 88.569
0.12589 39.71125675 88.188
0.15849 31.54615441 87.722
0.19953 25.06264778 87.144
0.25...

**restoration of signal**I have a question reguarding the restoration of a one-dimentional signal.
This signal enters a system which distorts the signal.
In order to restore it but maintain the shape of the signal as much as possible, what is the best approach?
I thought about using a wiener filter, but cannot find a function in matlab
that filters one-dimentional signals using the wiener algorithm
thank you
keren
"adi cohen" <kerenpur@yahoo.com> wrote in message <i1hodp$inp$1@fred.mathworks.com>...
> In order to restore it but maintain the shape of the signal as much as possibl...

**frequency of signal**Sirs,
I am trying to understand how to analyze a signal to see what type of
frequency component is contains. Let me explain my question through an
example.
assume I have a discrete signal as follows:
x[n] = [0, 2, 15, 18, 20, 12, 20, ...];
few obsevrations before:
1) the signal makes a fast rise between x[1] and x[2]
2) between x[2] and x[4], it makes steady rise
3) from x[4] it steep fall at x[5]
4) and then it make a steep rise at x[6]
In the above cases, which cases would contribute to frequency component.
1) In case of x[1] and x[2] where there is a steep jump, would ...

**signal frequency**Hi im really new to signal processing, im able to get signals from the sensor using winsound analog input, now i want to check the frequency range of the sensor, how do i proceed from here. i tried using fft but the plot does not respond well, i think i made some error in the programming
RAJKUMAR Palaniappan:
Yes, I think you probably did. By the way, what does "does not respond well" mean, exactly?
...

**frequency of signal**Hi!
I have a vector,signal, that oscilates between
[max(v)=50,min(v)=-60].
I like to know how many times amplituide of signal reaches the
threshold value, for example more that +30?
Do you have any suggestion?
If you have Simulink and Signal Processing Blockset, you can use
"Peak Finder".
Otherwise, you write some simple code. Maybe a loop like this:
% 'signal' is your... signal
% 'th' is the threshold; say 30, in your example
% 'count' stores how many times the signal passed 'th'
% 'flag' is just to count each peak only once
count = 0;
...

**Low signal**I am having a low signal problem somewhere is my house. The cable company
cannot seem to track it down. The signal level drops so low that my TV gets
fuzzy and my internet goes offline. As soon as the signal strength goes up
the internet comes back on and the TV is fine. I was thinking about just
adding an amplifier to my incoming cable line. What is your opinion?
Thanks.
Brad wrote:
> I am having a low signal problem somewhere is my house. The cable company
> cannot seem to track it down. The signal level drops so low that my TV
> gets
> fuzzy and my intern...

**what's the different between a frequency shifted signal band and a normal signal?**Hi,
I am facing some confusion about frequency shifting. I have sampled a
random noise signal at 48K . Now I have taken 5K to 11K signal band from
the main signal and shift this band at zero to 6K. I have done it
multiplying the 5K to 11K band signal by 2*cos(2.pi.5000.t). After
multiplying there is two band : one from 0 to 6K and another from 10K to
16K. Then using a a low pass filter I have taken the 0 to 6K band signal.
Then downsampled the signal by a factor of 4 to make the sampling rate 12K
. Now resultant signal seems to be smapled at 12K and it's band is 0 to
6K. (Is there an...

**How can I determine and calculate the frequency components in an audio signal, its fundamental frequency and its harmonic?**Urgent!!!
I have a wave file of a musical song.
The info on the wave file I get so far is as below:
(i)sampling frequency = 44100Hz
(ii)total samples = 9179268
(iii)bits/channel = 16
(iv)no. of channels = 2
(v)wave file length = 208 seconds
(vi)type of modulation = uncompressed PCM
I already generate the FFT on the wave file, but I got stuck now.
How can I determine and calculate how many frequency components in
the audio signal, its fundamental frequency and its harmonic?
and also,
How to calculate/determine the frequency bandwidth of the audio
signal?
I am a beginner in using MATLAB 6.1....

**Frequency Response VS FFT for measring frequency response of a audio ouput signal.**We have purchased the Sound and Vibration Toolkit and I have some questions.
From the frequency response example I looked at you measure the input then the ouput and the Vi gives you the difference.
I want to measure the audio frequency response a radio.
So all I have is the output I dont have the audio input to use as a reference.
How would I measure frequency response with the frequency rasponse VI with only the output audio signal?
I was also looking at the FFT example to measure the audio signal frequency response.
B...

**How much are the carrier frequency higher than the baseband signal frequency for a band-limited AWGN channel?**
When it comes to basic modulation method, ASK/FSK/PSK, there is a
sentence in some textbooks: the carrier frequency should be far more
than the baseband signal frequency. However, no one give the detail. I
need to analyze the data rate upper limit of a communication system
using QPSK coherent demodulation in a band-limited AWGN channel when
the carrier frequency and channel bandwidth is known. Shannon-Hartley
Capacity Theorem give some information, but without the carrier
frequency.
On Dec 19, 9:31 am, "X.Y." <Xieyu1...@gmail.com> wrote:
> When it comes to basic modulatio...

**Complex Wavelets: center frequency & bandwidth, designing a wavelet to extract a specific frequency range from the signal**I have a signal that I'd like to split into wavelet
coefficients corresponding to specific frequency ranges.
It appears that the complex wavelets (cmor shan fbsp cgau)
are designed for this purpose.
However, the problem I'm having is applying them to real-
world signals while the code appears to assume that a
signal is sampled at 1Hz. The function lets you specify
the center freq Fc and bandwidt Fb (for example cmor1-2
corresponds with Fb=1Hz Fc=2Hz). Obviously there is a
conversion: you can divide the Fc&Fb by the real-world
sampling frequency to get a new frequency ...