High-frequencies getting filtered

Hi all, not sure where to ask this, I hope someone can give
me some insight.
When I go to a website that allows me to stream audio and
video from my webcam - it pops up the flash dialogue box to ask my
permission....that's fine - then I choose to route my soundcard's
input to the stream instead of my webcam microphone and it works -
but for some reason, it rolls off the high frequencies, and it
sounds muddy and not clean and tight. With music, all the hi-hats
are gone, and all the sizzle is missing, not great!
I have been trying hard to find any info about HOW flash
grabs the audio, or where I can change the settings as to how it
interfaces with the incoming audio, but I can't find anything
anywhere. The only settings seem to be: line-in, and level - that's
it. No other audio controls of any sort...
...in testing - I tried listening to other people's streams
on the same site, and they have clear audio! I can directly A/B
between mine and others and mine is DEFINITELY filtered down....
I have tested my soundcard input into other recording
software, like ableton live and it is FINE. No filtering is
happening at the soundcard level, and recording into other
applications is pristine and perfect.
So, when I go thru the Flash interface, it is filtered - and
since I'm trying to stream live audio productions, it is
frustrating to say the least.
my setup - xp home, all updated, latest flash version 9....my
soundcard is an external motu-2408-mkII with ASIO drivers and
regular drivers
So, I guess my question is....since my sound input seems to
work fine, but only going through Flash does it get filtered - HOW
do I access the Flash drivers that affect this, Is there ANY info
about how flash interfaces with my audio anywhere....
Any advice will be greatly appreciated !! Thanks all, best
regards,
trevor

You might want to try out "Flash Media Encoder" for streaming
Live input from various devices. It has nice UI for setting Mp3
bitrates and can be used to publish "audio only" stream
also.

Similar Messages

Help Counting high frequency voltage spikes

Equipment: NI USB-6229 (250 kS/sec Analog In., 16 bit DAC, 32 bit Counters and internal clocks <= 80 Mhz)
LabView 14
Problem:
I have an experimental application where I need to count voltage spikes (integer #) caused by electrons hitting a sensor. These spikes can be as frequent as 500,000 Counts/sec. The spikes are not going to be the same voltage everytime, but they will be visible above the noise so I need to allow the user to select a Threshold Voltage that triggers a real count rather than noise spikes.
Attempts:
To count such a high frequency, I deduce that I need to use a Counter Input to read fast enough, HOWEVER, I wasn't able to find a way to set a threshold voltage for a Counter Input because I believe they expect a TTL signal anyways, which I won't have. To set the threshold, I realize that Analog Input reads can be triggered at a selected level which is great but the Analog Input Sampling Rate is only 250kS/sec which won't catch every count in my project.
I have a program that uses the Count Edges channel and it is accurate within 3% of the expected # of counts. I was just testing it with a function generator and the program doesn't count unless the signal's voltage is above 2-3 V which won't work for my application. I will post what I have. Does anybody know of a way to trigger off only at selected Voltage levels using counters, or know of a way to filter through the noise to get real spikes?
Thanks!
Solved!
Go to Solution.
Attachments:
ElectronCountsTest.vi ‏29 KB

Thanks for the reply johnsold. I didn't think to use a comparator but that is good to know that I have that option. I was and still am hoping for some kind of trick to do this programmatically. One other idea that I was playing with is offsetting two or three different Reads on the same signal to read the signal at different times. If this is a possibility, it may be able to double or triple my sample rate to 500k or 750kS / sec. Anyone else have any ideas on this solution?

Using iPod with high frequencies

Hi there - I'm having treatment for tinnitus (high-pitched sound in the ear). There is a treatment where you listen to music interlaced with high frequency sounds which is supposed to stimulate the brain & the cilia inside the ear. They have CDs available but recommend not to use iPod. My question is, if you transferred the CDs using Apple Lossless would the high frequencies come through? Bear in mind some of these frequencies are up to around 14 KHz and there are all sorts of subtleties in the signal. One question is transferring it to the PC using Apple Lossless, the other question is playing it back on the 5G iPod. I'm also thinking of getting a Nano just for this - would it play it back OK? Thanks!
MacBook Pro 15", 60 GB 5G iPod Mac OS X (10.4.4)
14 iBook, 768 RAM, 60GB Mac OS X (10.4.4)

This is only my personal opinion, which can be wrong.
First, human can only listen to 20KHz most, thats why the CD's frequency response only cover in the range of 20-20KHz.
For iPod - the apple mentioned the following
iPod is designed to provide the best-quality sound. iPod has a powerful 60 mW amplifier so it can deliver audio as loud as you want. It also has a 20 Hz to 20 kHz frequency response, which means you can hear distortion-free music at the lowest or highest pitches. Even the iPod headphones are designed to give you the best-quality sound. The earbud-style headphones rely on Neodymium transducers, a rare earth magnet that significantly enhances frequency response and overall sound quality. Most other headphones use aluminum, cobalt, or ceramic drivers; at the same size, the Neodymium driver is five times as powerful. Because the strength of the driver increases the accuracy of the sound, the iPod headphones provide a high-energy listening experience while minimizing distortion.
To ensure CD-quality sound, be sure to use a compression setting of 160 kbit/s (the default setting in iTunes) or higher when you "rip" tracks from your CD into MP3 format, or 128 kbit/s in MP4 format (AAC).
Therefore, if you rip the music from a CD, it does not matter whether it is MP3, AAC or Apple Lossless, it will no reduce the frequency response, however, there is noticeable difference of sound quality from different format, of course with Apple Lossless format being the best, but much bigger size.

High frequency quadrature decoder (NI PCI 6221)

Hello, i would like to ask you about high frequency quadrature decoder. I am using module in DAQmx for measuring linear position. For this i am using NI PCI 6221. My problem is that i want to use this for my interferometer and we need really high speed. So I tried to use External timing whitch should be possible for this card up to 80MHz. Unfortunatelly i always will get error message that there is some kind of owerflow and my program crashes. So my question is how to get all data form this card. I know that the buffer size FIFO is only 2 so if it is impossible to get all data so i want find another solution. Is it possible let my card work alone on 80MHz and only repeatly rewrite all buffer and just sometime ask this card for sending current buffer. I dont really need all the data, but when i will ask i need to know reall position. This high speed is really necessary because my interferometer is sensitive and i dont wat to lose any steps. If there would be any possibility how to work on 80MHz and only sometime ask for sending data with position, it would be great. Sometimes i will ask not for only current position but for full buffer because i want so see what is happening during some time period, but this task will be only sometime.

Dear BMAJTZ,
The counter frequency (the maximum speed available) is configured by the Task in the background. In our case, the counter is set to detect edges, so it always uses the maximum speed available. If an edge occurs, the count value increases by 1, and this accumulated count value (stored as a binary number) is read by the DAQmx Read VI, and converted to meters. So if your encoder input is slow enough for the 80 MHz card to handle, you won't miss any ticks, even if you only read the value occasionally.
You can find further information about counters and encoders on these links:
http://www.ni.com/academic/students/learnlabview/digital.htm
http://www.ni.com/white-paper/7109/en
Also if you can tell me the approximate frequency of your encoder signal, and how often you nedd the position info, I can do some benchmarking for you to see if your card is capable of the task.
Best regards:
Andrew Valko
National Instruments
Andrew Valko
National Instruments Hungary

Only Noise (high frequence pulses) on Firewire Interface Motu 828mkII

hello,
i drive Logic 7.2.3 and Wave Burner 1.2 a long time, since yesterday i get only noises and high frequence pulses on my interface.
I Tunes and Quick Time works well whith Motu/Firewire.
Only Logic and Wave Burner does!!
I tried different settings in Logic or in Audio-Midi-Configuration.
Additionaly i get sync problem messages in Logic, also in WB.. the SPL is not moving right!!
Has anybody an idea??
Thanks
Patch

There are lots of posts on this topic - the search function would have turned them up. Try this:
http://discussions.apple.com/thread.jspa?messageID=1477845&#1477845

DAQmx Error 89137 When trying to make a high frequency measurement.

I am using a PCI-6602 Timer/Counter for multiple measurements on a serial interface...
I have the clock line connected to Gate0, the enable line to Aux0 because I need to make a two-Edge seperation measurement between the two later...
But I also want to make a "Period/Frequency Measurement (High Frequency with Two Counters)" measurement...
This requires that the signal to be measured is on Source0...
I implimented the following Code:
void meas_FP_Freq(float64 *Freq0, float64 *Freq1)
TaskHandle CLK0_Freq, CLK1_Freq;
DAQmxCreateTask ("FP_CLK0_Freq", &CLK0_Freq);
DAQmxCreateTask ("FP_CLK1_Freq", &CLK1_Freq);
DAQmxConnectTerms ("/Dev3/PFI38", "/Dev3/Ctr0Source", DAQmx_Val_DoNotInvertPolarity); // Gate0 to Source0, No Error....
DAQmxConnectTerms ("/Dev3/80MHzTimebase", "/Dev3/Ctr1Source", DAQmx_Val_DoNotInvertPolarity);
DAQmxCreateCIFreqChan (CLK0_Freq, "Dev3/ctr0", "", 6000000, 6500000, DAQmx_Val_Hz, DAQmx_Val_Rising, DAQmx_Val_HighFreq2Ctr, 0.001, 4, ""); // High freq measurement
DAQmxCreateCIFreqChan (CLK1_Freq, "Dev3/ctr1", "", 6000000, 6500000, DAQmx_Val_Hz, DAQmx_Val_Rising, DAQmx_Val_LowFreq1Ctr, 0.001, 4, "");
DAQmxReadCounterScalarF64 (CLK0_Freq, 3.0, Freq0, 0); // Run-Time Error -89137 Specified Route cannot be satisfied..etc
DAQmxReadCounterScalarF64 (CLK1_Freq, 3.0, Freq1, 0);
DAQmxDisconnectTerms ("/Dev3/80MHzTimebase", "/Dev3/Ctr0Source");
DAQmxDisconnectTerms ("/Dev3/80MHzTimebase", "/Dev3/Ctr1Source");
DAQmxClearTask (CLK0_Freq);
DAQmxClearTask (CLK1_Freq);
The "Low Frequency" method works fine, but the resolution is too low...
Every help file I've read indicates I can use different PFI inputs for measurements... What am I missing?

Hi,
The reason that you are getting the error is the PFI lines are being reserved twice. You don't need the DAQmx Connect Terms functions in your code because the DAQmx driver does this for you automatically. If you still receive an error after doing this, try to changing the low frequency counter number. I hope this helps you with your application.
Regards,
Hal L.

High frequency

Hi everyone, im pretty new with Labview, and I need a help. I would like to simulate square wave with high frequency (40MHz).
1. Can anyone help me, how can I simulate the signal (test2.vi) in a moving (time) axis?
2. I would like to catch the datas and write it into .txt or excel. I found this example (0807-LVM_Beispiel.vi). Can I get the datas like this from my 40Mhz frequency generator?
A little help would be nice. Thanks.
Attachments:
test.jpg ‏525 KB
test2.vi ‏29 KB
0807-LVM_Beispiel.vi ‏88 KB

thanks for your help.
Ive been searching, and now I've changed my test2.vi into test CIC.vi and modified it. If you may see it, im trying to simulate the signal with frequency 40MHz and, with sampling frq. 800MHz and sample rate 1000samples or max. ~300.000samples (and save it in a txt.file). Actually, my task is, that im gonna need to make a labview program that can take as many points as possible, that might be not periodic. I mean, we gonna use NI card (in near future, not bought yet) to take some input datas, and to get all the data-samples in high frequency range. Is it possible to make such a program (capture the data) without knowing in the first place which NI card that we are going to use. But i believe, we gonna buy a digitizer, digital I/O and might also mxi controller (I've looked at the offered device list) from NI. Thanks a bunch. Is it much easier after buying the devices? (like getting the device's driver and maybe program that support it).
One other question, in my test CIC.vi, im saving my points into .txt file (only the amplitude). How is the trick to take also the x-axis points (time axis) and save it in the same .txt file.
Attachments:
test CIC.vi ‏49 KB
CIC 1 sub.vi ‏21 KB
Save 1Data.vi ‏18 KB

Daq 6211 high frequency ouput

HI guys.
Ive got my hands on a USB 6211 daq device. Im trying to generate a high frequency pulse output from one of the 2 counters. The frequency is in the range of 5 to 20 kHz. Can someone tell me if thats possible with this USB 6211 device?. Ive been searching but cant seem to find the answers. Are the counters on this device just for reading HIgh Frequency inputs or can they ouput them also. Any help would be much appreciated.
Solved!
Go to Solution.

That manual has helped a lot. I should have looked at properly in the first place. Thanks .
I have one more question if anybody can help. I'm using the daq 6211 to create a pulse train to control a stepper. The stepper driver takes in a pulse which in turn will turn the stepper and the frequency of these pulses determines the speed.
My problem is that, using the counter examples in labview, I only have an option to create a continous pulse train. I would like top be able to dynamically adjust the frequency while the vi is running and Ideally i want to be able to ramp up the frequency so that the stepper can get to a high speed. If i try to adjust the controls with the example vi's there is no change in frequency unless i stop it and start again with a different frequency.
Has anyone come accross this themselves or am i missing something obvious??.

Bandpass filter amplifies only noise at high frequencies and saturates the opamp output

I have designed a fourth order bandpass filter using the opamps TL081C. It is designed to operate at a center frequency of 40 kHz with a bandwidth of 2 kHz and a gain of -12.5 . I am using an SCB-68 board for data transmission and reception, one channel each for transmitter and receiver. I have grounded the adjacent channels to both the transmitter and the receiver in order to avoid crosstalk. However, at the output, I get a signal which looks like an amplitude modulated signal and is, most probably, noise. The amplitude of this signal is always around 9V, no matter what is the amplitude of the input (even if the input is 0V, the result is the same). If I scale down the whole BPF to operate at a center frequency of around 20 kHz, everything works fine. Therefore, I think the problem lies not in the design of the BPF but the use of the board at higher frequencies. Please reply as soon as possible.

You have done something wrong. You should read the manual for both the SCB-68 and your DAQ card once more. In such cases I often use MAX, and a battery as source. Then a DAQ input is not connected (floating) you will see measurements like you are doing now. Some high level voltage often modulated with mains frequency.
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

NI Mydaq gain loss at Higher frequencies

Hi There,
I am using a MYdaq for my student project, I am using this is an audio sine wave generator and analysis tool as part of the project.
I am sampling well above nyquist of my highest frequency (20K) at 100K sample rate both on my OP DAC and IP ADC and I have a buffer size of the same size on the I/P and output.
I am using the audio L/R inputs and outputs (AC coupled) - This is looped fro the purpose of this excercise.
When I generate frequencies (via the Sinewave Vi in labview - "NI_MABase.lvlib: sine waveform.vi" and my FS and #s is both set to 10000.) i get a drop in level above approx 10K starting at about -1dB up to -3dB at 20K
Can anyone help me in tracking down the cause of this?
Regards

Hi,
Just to for my own sanity, have I got these values right?
- Sampling at a frequency of 100kHz. (Analogue Input and Output)
- Intending of sampling a 20kHz signal.
The specifications of the NI myDAQ can be found here. These specify that the device can sample up to 200kS/s for both Analogue Input and Analogue Output, meaning that the maximum clean sinusoid we can both generate and acquire should be 20kHz, with 10S to represent the wave. Higher frequencies will require lower samples and the signals will look more chopped and aliasing will occur (20kHz*10S = 200kS/s). In order to appropriately measure the 20kHz wave, we need to choose a maximum sample frequency of 200kHz for clean waves. With this in mind 100kHz sample rate should be okay.
Is it possible for me to check the code that you have written so far? What I imagine could be happening is that we're seeing these issues due to the slowness of software. If you look at your code and the DAQ VIs are continuously having to check what values to write, rather than having these values delegated down to the hardware layer prior to running the task, this could be the source of the issue. This is because in software, there is a maximum update rate of 1kHz; this is why all of the base clocks in LabVIEW software are 1kHz clocks. If we're constantly having to poll what kind of digital output values we want to write, this will affect the consistency of the generated signals.
Kind Regards,
Alex Thomas, University of Manchester School of EEE LabVIEW Ambassador (CLAD)

IO fails working for low frequency, but work well for higher frequency

On our customized VU440 board, we did a IO performance test for each bank and found a strange problem, in the design,we send out 24bits Pseudo random data and loop back this data to the same bank with our testing board, on which the pins for tx and rx are only connected in short circuit, one differential clock is transfered to single-ended global clock in the design, using IBUFDS+BUFG to provide the global clock for tx module and rx module.
howeve, we use vivado debug tool to check the data looped back, only found when the clock is 200MHz around, the data is correct, but if fails to get correct data when the clock is much lower, for example, 10MHz ~100MHz. And from the waveform we got, we identified the status for some pin was un-normal when the data bus failed to get correct data.
we have found the problematic IO pins, but did not know why the problem come out, normally, we think it's normal for the IO pins fail to work when the frequency is too high, but in our case, the issue is on the contrary, we don't understand why it works for some higher frequency but fail to run when it's much lower.
we now try to check our PCB also, but have no clue at present.
Some guys have any idea or suggestion to check for the reason?
thx~

Hi,
What is the IO standard that you selected for the TX and the RX. How long is the loopback cable?
Do you have proper terminations on the board? Because in general, all IO Standards need some terminations which are mentioned in the respective SelectIO user Guide for that device. Please check that.

NI PCI-6115, problems in high frequencies

Hi,
I'm not sure if this is the right place to make this question but let's try..
I try to measure the frequency response of the output impedance from a certain switched-mode converter using NI PCI-6115 (I inject sinusoids into output voltage and measure the output current). I get a nice plot but there are some problems in high frequencies. It seems that the measurement card makes some unexpected peaks. I use the network analyzer (Venable) to verify the results and beyond 200 kHz the results do not match. I attached the plot with the results from both methods (MC = PCI-6115, Venable = network analyzer). Does anyone have any idea what could cause this difference in high frequencies? The measurement set ups where exactly identical.
Thanks!
Attachments:
Doc1.pdf ‏87 KB

looks like a resonace at 400kHz...
Are you shure that the input impedances of both setup are the same? Are you injecting with a transformer and build a LC resonator with the MC?
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

Agilent E4980A lcr meter reading high D at high frequency

Hi I have a quick question on my agilent E4980A. At high frequencies ( i.e. 100MHZ using the agilent E1645 test lead) I get high Df readings. What could be causing this?.
Thank you

This isn't a question for NI. You need to ask Keysight about their hardware/software.

High Frequency Sound Bug on iOS 8

From time to time I turn on my bluetooth headphones, put some music and almost get deaf by a super high frequency sound coming out from them. First time it happened I thought it could be the headphones, turned them off just to hear that strange treble sound (like an old Modem) coming out from the iPad speakers too, then I rebooted the iPad and it looks fixed.
Yesterday it happened again, but after reboot sound was kind of back but still wonky, like blown heaphones, when you cannot hear bass and it has a buzz all the time playing with the songs.
Looks like this is related:
Weird static/high frequency sounds while streaming Netflix.
Is there a proper channel to report this?

High Frequency Noise from Headphones Out Jack

I have isolated the following issue to audio that is monitored via the headphones output on the back of my iMac:
I've been encountering a very high-pitched (and at times a cycling through high frequencies) noise when working with headphones to monitor audio. It's not the headphones and the problem is not limited to any single application. The noise is sometimes barely audible, and it comes and goes - but repeatedly and often. Sometimes the frequency of the noise is so high that I can imagine that those with poor or compromised hearing wouldn't even notice it. But the highest frequencies are still detectable - kind of like a faint ringing in the ears or a ringing television set that has its volume turned all the way down.
I've done everything I can imagine to troubleshoot the problem including asking a Mac genius, but nobody seems to have encountered this before. The noise can be triggered off (not masked) by any other incoming audio, but eventually it reappears. I will be editing a file, the noise will appear, and I can literally silence it for the moment by pressing a volume key or playing back a portion of audio.
Anyone else experiencing this issue? Is there a fix? I do a lot of audio engineering and this problem is very distracting. I haven't purchased any outboard gear to monitor with yet, so I don't know if I will hear this noise through an external audio interface or not. Thankfully, this noise isn't being recorded to disk. It appears to be a little monster that is haunting only the playback.

OK, It is very easy to reproduce the problem, just follow this steps:
(1) Insert any headphones to iMac.
(2) Do NOT play any iTunes or any application with sound.
(3) Now, set volume with the volume control keys on your keyboard, set it to the MAX.
(4) You can keep pressing on the increase volume key and every time you hit the key you should hear a sound.
Just as when the sound stop, you will hear a high pitch. Keep repeat step 4 and wait a while, then occasionally you will hear a high pitch sound that will last to longer than 30 seconds. The high pitch will be even easier to reproduce if you alternate before decreasing volume and increase volume by 1 level, each time, wait and you will hear the high pitch too.
This high pitch sound can be heard on external speaker plug into the headphone jacks too.
BTW, I turned OFF WIFI, Bluetooth, removed all USB devices except keyboard and mouse, adjust monitor brightness, they have no effect on the high pitch, it is still there!
I am going to call the Apple Care tomorrow. Will keep you guys posted.
Message was edited by: chienlim

High-frequencies getting filtered

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