i enter the ECG signal on the lab view through the sound card and make program that read the ECG as sound file and display it on chart

[kerelous]

• i record the ECG signal through recorder abd be as a sound file
• i open the lab veiw help and found program that display the sound signal all it that if the sound file duration is 2 min the displaied signal will be from 0 to 2min in one shoot
• so when i store sound file for 1 hour there is error and display message " no enough memory "
• so how i can increase this memory to display sound file for ECG signal record for 24 hour

[Coq_Rouge]

If the recording software is made by you. You could try to reduce the samplerate.  Another trick is to read and process data in chunks.

If the recording software is made by you and in Labview please post so we can take a look at it. In order to suggest the best way to help you. I have some ideas like reducing the samplerate by downsampling. For a ECG signal a samplerate equal to say 2 Khz may be adequate

Also what are you using the recorded signal for. As you may know sound cards block low frequencies and hence distort the ECG signal. But for say heart rate analysis a sound card may do the job

[Steve.J]

For 24 hour recording, you really want to store the acquired ECG data to disk as you are collecting it - it seems that the VI that you found to acquire the sound clip is storing it to DRAM memory.

As Coq pointed out, the sound card is also acquiring the data at higher sample rates than necessary, so this also wastes a lot of memory.  ECG data is normally sampled at a few hundred samples per second - maybe 1kHz max for research applications.

Please tell us more about what you are trying to do with the ECG data to help point you in the right direction.  Also please note that there is a LabVIEW Biomedical User Group at www.ni.com/biomedusers where you can also find a free download for a Biomedical Starter Kit that includes a data logger and ECG analysis VI's that may be very helpful.

[kerelous]

first post my software under the my question it a program that that read the wave sound file and display it as a signal on chart you can record any sound from the recorder in the window and convert it to wave type and open it from the program

the program work for sound file duration to 15 min try to open sound file dut its duration up to 1 hour ther error will be appear " there are not enough memory "

second i have ecg simulator that is a device that genrate ECG signal and i take this signal and pluged it in the jack of the mic and record so i have the ECG signal as sound file

i want to do this becouse i do ECG HOLTER and it is a device that record the ECG signal for 24 hour and then display all the record ECG on the computer 

[kerelous]

i want to do ECG HOLTER and it is a device that record the ECG signal for 24 hour and then display all the record ECG on the computer 

and i store the ECG from the mic to be as a sound file

[Steve.J]

But what do you want to do with the ECG data - just view it in a chart format? Or are you trying to process it and extract information from it (like the heart rate) over the 24 hours? 

Is this for a class you are taking, or are you doing research?

Again - the signal as recorded by the sound card input will be modified by the frequency range of the audio input...it is an AC coupled input and therefore will block some of the low frequency content of the ECG signal coming from your simulator - it will likely suppress most of the P and T waves.  It would be better to record the data using a low-cost USB data acquisition device like the NI USB-6008 which can acquire down to DC.

[Coq_Rouge]

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@kerelous wrote:

i want to do ECG HOLTER and it is a device that record the ECG signal for 24 hour and then display all the record ECG on the computer 

and i store the ECG from the mic to be as a sound file

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Please remember that good questions draw good answers. We do not mind helping other people in here. We can give you a push in the correct direction. And if you show that you put in some effort by your self help you out more. But to give a complete application most of us will require a signed contract 😉

So please give us more details about what you are going to do with your data. Your project is indeed doable in Labview. But depending on what you want to do with your data. A soundcard may or may not be optimal. Soundcards is made for sound and will not be very good for frequencies below 10 Hz approximate. And this is something you should discuss with your professor

[kerelous]

i want only display the ecg signal on chart and calculate the heart rate over 24h

[kerelous]

first sorry for misunderstood due to my unclear question

i have a task to do ECG holter [a device that record the ECG signal for 24h]

so i record the ECG signal form sound recorder over 24h and then i have the ECG signal as a sound file if you play it on WMP you can hear the sound of the ECG by this i finish apart of my task

and the remain part of my task is to display the record ECG on chart and calculate the heart rate

then i try to display the signal of the sound file [ECG signal] and appear on the chart over 24h [the all record ECG over 24h appear on chart in one time ]

at finish my front pannel will be a big chart display the record ECG over 24h and a small chart display a curve of the change in heart rate value over 24h

[johnsold]

Your File data graph is only 263 pixels wide and the graph is only 561 pixels wide.  So, you can never see more than 561 points at a time.  Feeding more points than that to the graphs is useless.  LV will manipulate the data in some way which is not well defined to reduce the data you connect to the graph to the number of pixels available for display. 

As other responders have indicated you probably have a sampling rate issue.  Sound cards sample at rates of tens of kHz or faster which produces very large numbers of samples over the 24 hour recording period.  Sampling at 100 Hz is probably fast enough for heart rate analysis although it is a bit slow for ECG waveform interpretation.  At 100 Hz you would have 8 640 000 samples in 24 hours which is quite manageable. 

Lynn