Sine wave on startup

I searched for this all over and can only find references to start up sounds like 5 beeps or breaking glass.
A couple of times I have started up my PowerBook G4 to have it make a single mid-ranged sine wave sound for a second or so. Then it waits for a few seconds and makes the normal startup sound. Everything seems to be running fine, except that hard drive access has become pretty slow. I tried running repair disk and it did nothing. What does the sine wave sound signify? Like I said this has only happened a couple of times, and is the only unusual error I've gotten.
Thank you,
Andrew
PowerBook G4 17" Mac OS X (10.4.8)

sometimes slow drive access means failing hard drive.
all kinds of noises could be made by failing drives also.

Similar Messages

USB-6009 Sine Wave

Hi,
I am new to LabView and am having some trouble. I need to input two sine waves into a USB-6009. I have a voltmeter that should read the output. Two of the problems that I have had thus far: I can only use "On Demand" in DAQ Assistant and even when I throw the DAQ Assistant into a while loop I still do not get a readout on my voltmeter. Any suggestions? Thanks for the help.

That is confusing. You say you need to input 2 sine waves into a 6009 and that to me implies that you are doing a DAQmx Read. Then you say you have a voltmeter to read the output. That implies you are doing a DAQmx Write. If you are really doing a write from the 6009, then on demand is, of course your only choice. As the specs clearly indicate, the output of the 6009 is strictly software timed so you would need to pass a sine wave point by point and then you would have very little control over the frequency. And, again as the specs clearly state, the fastest output rate you could expect is 150Samples/sec.

Simultaneous analog output 1k sine wave and data acquisition

Although many topics of simultaneous analog output and input can be found in NI Developer Zone, I have not found a case similar to my project. I'm trying to generate a 1kHz sine wave by using the analog output of NI DAQPad-6070E, and acquire one channel input signal simultaneously. I found most of the examples can not work properly above 100Hz. Any suggestions are welcome. Thank you.
Jian

I have sucessfully solve the problem when I observed the increase of
scan backlog number. Simply increase the buffer size of AI/AO and you
can make the 1kHz sine wave output and data acquired properly.
On Tue, 3 Feb 2004 09:03:07 -0600 (CST), jujian wrote:
>Although many topics of simultaneous analog output and input can be
>found in NI Developer Zone, I have not found a case similar to my
>project. I'm trying to generate a 1kHz sine wave by using the analog
>output of NI DAQPad-6070E, and acquire one channel input signal
>simultaneously. I found most of the examples can not work properly
>above 100Hz. Any suggestions are welcome. Thank you.
>
>Jian

Unable to generate sine wave

Hello everyone!
I am currently working on my Bachelor project at a company. i am stuck with a problem.
I have designed a labview program for vibration test system. I have used cRIO 9076 as the controller with NI 9263(as D/A) and NI 9234(as A/D).
The loop works as follows. the input is given from the labview program. it is then sent to the cRIO. the output of CRIO(that is output from NI 9263) is given to the amplifier. the vibration shaker vibrates based on the input from aamplifier. then the accelerometer detects the vibration and sends it to the NI 9234 and loop repeats iteratively. since i have designed a sweep sine vibration system, the output of cRIO is a square wave. it should be sine wave.
the probelm is i am getting a square wave as output from my NI 9263 which should be a sine wave output. I have two subVI where i use nominal to binary convertor(for NI 9234) and binary to nominal (for NI 9263) as calibration mechanism.
the question is where have i went wrong? what should I do to get a sine wave?
PS: on searching NI i found out some formulas (to generate sine wave) and designed a FPGA and LabVIEW program to generate a simple sine wave and got a sine wave. if that formulas is to be included where should i include that?
Thanks in advance.
Regards,
Vishal.

Without seeing your current code, there is no way we can even uess as to why you are creating a square wave instead of a sine wave.

How to measure time difference between zero crossing of a sine wave and rise time of a pulse on a same graph?

I have a 50Hz sine wave and a pulse signal on a same graph. The phase difference between two is between 0-90 degrees.
Now I need to calculate the time difference between (when the sine wave crosses zero volts) and (when the pulse rises). The frequency will stay approximately same for both signals.
The application is for a three phase generator. In simple words, when the time difference between the zero-crossing of sine wave and the pulse rises increases, that means that the load on the generator has increases.
I am a beginner user of LabView (version 9, 2009), maybe it is a very simple problem but I've been pulling my hair out for the last few days and coudln't figure anything out. Any help would be greatly appreciated. I am using DAQ USB-6008 to measure these voltages and pulse from the generator and a sensor
I have attached a jpg (a graph that i just made with excel to explain). The time 't' is what I am trying to measure
Cheers
Awais
Message Edited by awais.h on 03-30-2010 11:20 PM
Message Edited by awais.h on 03-30-2010 11:21 PM
Solved!
Go to Solution.

Hi
Thanks for the code but I'm afraid it won't work. Like you said the probability of choosing a value that is on both graphs may not happen. This is something that I would like the code to do automatically.
But I did use the previous code posted and made some modifications to it and it seems to work perfectly. Now the next thing is to be able to get just that one value that tells you the first time difference.
Here is what I get using that code.
As you can see from the t Values. I only need the one that is highlighted. If there is a way to filter out the rest it would be great.
I was thinking of a while loop and as soon as the value is higher than 3E-5 it would store the number and stop the loop, but I'm not too familiar with arrays in labview.
Here is the the code modified.
As you can see, it wasn't that big of a modification and it still is your code.
I will keep trying.
Thanks for the help
Attachments:
FinalShockSpeed.vi ‏55 KB

Question on the result of using Wavelet transform on sine wave

Dear all,
I have apply the Wavelet transform on a 50Hz sine wave. The result is shown below. But I don't understand the result of Wavelet transform. Anyone can help me? Thanks.
Victor

You seem to have something against the FFT, yet continually compare other transforms to the "sweet spot" for the FFT, ie. sinusoidal and periodic functions. Without trying to write a treatise on the subject (there are many fine books), a few observations.
The primary purpose of any transform pair is to perform a rotation in function space, for the FFT we are familiar with the time domain and frequency domain. The wavelet domain is not so simple. The FFT is very effective for sinusoidal and periodic functions, ie. those that have no localization in the time domain. If you have a sinusoidal input, the infinite signal in the time domain can be reduced to a pair of numbers (one if you take the power spectrum). That is very efficient, other periodic signals can usually be approximated by a small number of terms.
Wavelets on the other hand are chosen to be localized in both the time domain and the wavelet domain. If you look at a periodic signal like your sine wave, you see a mess, and to recreate the input signal you will need to keep an awful lot of the points around for the inverse transform. You may be able to set the last 1/3 to zero, but that's it. To see an effective application, you should be looking at localized functions, like an impulse. Put an impulse into the wavelet transform and you get something that is still a bit complex, but pretty simple. The FFT of an impulse contains components at all frequencies and the wavelet clearly wins in this case.
On paper, there is usually a clear choice, and the FFT almost always wins for spectral estimation. On the other hand, if you are trying to compress "real world" data, for instance an image, then there is a choice to be made. Standard JPEGs are FFT based, you take the FFT and try to keep just the largest frequency components. As you probably notice, edge contrast usually suffers, especially at higher compression. With wavelets, it is typical to have slightly better contrast leading to better preservation of details for a given compression.
In short, my opinion is that transforms are useful when they simplify the problem. Wavelets do not simplify the representation of a sine wave.

How do I make a sine wave in illustrator?

Hi,
I started a thread earlier this evening but I think that I accidentally flagged it as "solved" or something like that (I'm new to this forum). So I'm trying this again. I want to know if there's a way of creating a sine wave in illustrator. I've managed to create a cosine wave by using the zig zag effect on a line and choosing "smooth". But I can't seem to find a good way to make a sine wave.
This is the difference for anyone wondering:
I want a sine wave just like the picture above.
Thanks for the help!
ekmanch

ekmanch,
As I (mis)understand it, to create a single full sine wave, you may:
1) Create a horizontal line 2.5 times the length of the desired full sine wave (or you may adapt the length later);
2) Effect>Distort & Transform>Zig Zag with 4 Ridges per segment and Smmoths Points and the desired height as the Size (or you may adapt later);
3) Object>Expand Appearance;
4) Object>Path>Add Anchor Points;
5) With the Scissors Tool cut where the sine wave starts and ends;
6) Ungroup if needed and delete the end bits (and adapt the length/height if needed).

How can i measure only the valley voltages of a sine wave in labview 7 express evaluation version?

I am trying to convince my company to send me to purchase labview and send me to classes for labview.
I am trying to put together a small demo for them using the Labview 7 express evaluatin copy that I recieved.
What I am wondering is how can filter out everything besides the valley peaks on a sine wave.
What I am trying to accomplish, is create an example showing that Labview can sameple from a sine wave, read about 5 "valley" points of the wave, evaluate these based on a value that i can define, and signal pass or fail.
attached is a picture of what i have so far
Ryan
LV 7.1
Attachments:
progress.bmp ‏3841 KB

Hi,
I built a VI using LabVIEW 7.0 that detects the valleys in a sine wave. It uses the 'Peak detector' VI that I believe is available in the evaluation version.
(Functions palette >> All Functions >> Analyze >> Signal Processing >> Time Domain >> Peak Detector)
I have attached a VI as well as the screen shots its front panel and block diagram.
I hope this helps.
Sincerely,
Feroz
Attachments:
valley_detector_bd.jpg ‏36 KB
valley_detector_fp.jpg ‏72 KB
valley_detector.vi ‏29 KB

How can I Write a sine wave in an Access-file?

I measure a sine wave in LabView 6i. How can I write the datas automatically to an Acces-file, at the same time?
In my program, I managed it with Execute SQL.vi, I change a number in a SQL statement(String) -> after this I push start and then it writes the statement in the Access-file.
The problem is, it writes only one data per measurement in the file. How can I write all datas in the Access-file and measure the wave at the same time?
Thanks for help!
Attachments:
getwave.vi ‏49 KB

On the waveform palette, you will find a "to components" vi that you can break out the array of the waveform. You can then, using a for loop write all of the values from the waveform.
Better yet, there are examples in the database toolkit manual on pages 3-13 to 3-15 that deal with reading arrays (and even has a waveform example).
Good luck!

How can I calculate the frequency of a 2-4Hz three phase sine wave in 50msec?

I want to calculate the frequency of a sine wave using either all three phases or just one, but I want to know the frequency after 50 msec, I don't want to have to wait for a full period.

I have a mathematically sound suggestion but I do not know how well it will work in application. Most period measurements measure the time between a full period or several periods to eliminate the error introduced by the measuring device. Essentially the device error is made insignificant.
Mathematically you can do much more but there is a tradeoff between recording less information and knowing (or assuming) some values. For instance, if one knew the amplitude and could calculate the derivative of the signal, one could calculate the frequency. A sine wave can be represented by the function: A sin (BX)=C , where A is the amplitude, B is the frequency, C is the present measured value. If the equation is solved for X, we get: X=(sin^(-1)(C/A))/B. The d
erivative of the first equation is AB cos(BX)=C. If the equation for X is now substituted into the second equation, we get, AB cos(B (sin^(-1)(C/A))/B)=C. Solving for B we get B=C/(A cos(sin^(-1)(C/A))). Remember, we already know A and C, so we are done.
Practically every step and assumption in the above argument introduces possible error which will affect the accuracy of the frequency. Unfortunately it is a trade off and that is why at least a whole period needs to be measured to get an accurate frequency.
Jeremy Braden
National Instruments

My Sine Wave File sounds different in Logic than iTunes

I am working on creating musical compositions with embedded sine wave patterns (which I am generating in a foriegn application). These sine waves are designed to entrain the brain to different frequencies to facilitate in stimulating meditative states of consciousness in the listener.
Unfortunately, when I import my sine wave audio file (in .wav format) Logic changes it and the rhythm is frequency is twice as fast! When I play the file in iTunes it sounds just the way I generated it, but when I import it into Logic through the audio bin or simply drag and drop onto the arrange window, it sounds different and cannot work for the precise control I require for my compositions.
Does any one have any idea why this is happening or what I can do to import my audio file without changing it?
Thank you so much for any ideas/assistance,
Devlin Dewitt Donnelly

Hi DD Smooth,
you should check sample rate settings on your original audio files and make them match the sample rate settings on your logic project prior to importing them. Sounds like you are generating 48khz .wav files in your foreign app and Logic must be set to 44.1khz by default. Or the other way around
Message was edited by: Imol

How to change the phase by 90 deg of a sine wave

Hi
Does any one know how to change the phase of a sine wave by 90 degrees.
Mal

Hi Malkoba,
Thank you for your post.
Having looked at your VI I can say that you have created the correct inputs to the 'Sine Waveform.vi'.
However the dial you had created had no affect as it was not wired into it the 'Sine Waveform.vi' on the block diagram.To fix the problem I have wired the 'Phase' dial into the 'phase' terminal of the waveform generator. This now changes the phase of the sine wave during runtime.
The dial also now has a digital display (numeric box below it)- this can be used to read the dial's value, or feed in specific values into the control.
Please find a modified version of your VI below.
Regards,
Field Sales Engineer | National Instruments | UK & Ireland
Attachments:
NI_phase shift sine.vi ‏31 KB

Best fit lines for loops and sine waves

I am trying to find a best fit line that will work for sine waves and loops (hysteresis loops). I can get the sine wave just fine, but when I switch to a hysteresis it just puts a line across the middle (I assume because of the 2 y values for every x). I am doing data acquisition that will take in both forms and graph them. I tried a polynomial fit and it doesn't work at least the way I implemented it and I tried a few others but it looks like they are all function based. Also, my y values are coming out of a Bessel filter. I don't think this would be affecting anything but I thought I would put it in here incase it does.
Did I miss one that I haven't tried that works for my application?
Thanks
Patrick

RiversDaddy wrote:
... currently I am doing it by looping and reducing the error towards zero to fit the amplitude and phase. (I know the frequency). If this is what you are looking to do then I will help, or should I be doing things differently? All of the functions I have found to filter or extract tones seem to introduce a larger frequency of phase error than i get using this method, but am I missing something?
"looping" is a bit vague. What is the actual algorithm to find better estimates (e.g. levenberg marquardt, etc.)
What problems did you have with extract single tone. Can you show some data where the results from it are not good?
LabVIEW Champion . Do more with less code and in less time .

How to create sine wave and step input using cwgraph in VB 6.0

hello..
i'm doing my master's project now. i'm stuck on how to create a sine wave and a step input using the cwgraph using VB 6.0. please help. thanks.

hello..thank for the reply.
i'm having problem with my coding using cwgraph. can anyone help. everytime i do the full compile, there's error.but it can still can run, but can't convert to application form.for your info, i'm using RTscope and cwgraph to plot graph.the error is in the cwgraph coding.below are part of the coding with error. and can somebody tell me how to add cwgraph component in the VB? i try adding component, but it's not in the list of component,and i've browse for it already too.i'm doing the software at home, but i'can run it at my lab cause cwgraph component is not listed.please help.
Dim countTime As Integer, count1 As Integer, countFreq As Integer, countVolt As Integer
Private Sub cmdRun_Click()
If cmdRun.CausesValidation = True Then
cmdPause.CausesValidation = False
tmrOsc2.Enabled = True
tmrOsc3.Enabled = True
Else
cmdPause.CausesValidation = False
tmrOsc2.Enabled = False
tmrOsc3.Enabled = False
For count1 = 0 To 100
Data1(count1) = 0
Data2(count1) = 0
RT1.Value(1, count1) = 0
RT1.Value(2, count1) = 0
RT1.Refresh
CWGraph2.Plots(1).PlotY count1 ' THIS CODING HAS AN ERROR ...
CWGraph2.Plots(2).PlotY count1 ' THIS CODING HAS AN ERROR ...
Next count1
End If
End Sub

How to count the number of cycles in sine wave

Hi,
I am new to Labview. I have labview 8.2 version and my dataacquisition is NIDAQPAD6015. I could write a program to generate a sine wave of desired frequency through simulate signal. My question is how do i measure the number of cycles for this sine wave as soon as I run the program. Hope my question is clear.
Ravi Mokirala

To find the offset (which in this case is the Y value midpoint around which the sine wave is symetrical):
Capture more than one cycle. Find the min and max values. Subtract Min from Max and divide by 2. Then subtract this result from the Max value (or add the result to the Min value). This is the offset.
To count the number of cycles where the offset is unknown, just use the first data point value as a reference. If the next data point is more positive, then count the number of times that the first data point is repeated and the next data point is more positive. Of course with DBL data type, you probably would not get the exact same value as the first data point, so you need to use In Range with a very tiny limit. It all depends on your signal amplitude, frequency, and sampling rate.
Example: Lets say your first data point value is 0.5 and the 2nd point is 0.55. You need to look for another value that is between 0.48 and 0.52. Then read the very next data point value. If it is greater than the previous value, add one to the cycle count. If it is less than, you are at half a cycle, do not add to the count.
- tbob
Inventor of the WORM Global

Sine wave on startup

Similar Messages

Maybe you are looking for