High frequency and resolution with 6036E

I am trying to drive a triangular wave signal with about 250Hz, with the greatest resolution possible. However, due to buffer restrictions and sampling restrictions, I can't seem to be able to produce more than about 10 Hz. Is there a really good way to produce such a higher-frequency signal, with no loss to resolution?

It looks like you need a faster output card. The best that the 6036E can do is about a 10kHz update rate. Do the math and that means cranking as hard as it will go, the card will only put about 40 updates in each cycle of the output waveform.
From what you said, a 10 Hz signal is ok. So if you extrapolate out to 250Hz you need to be looking for a card with an update rate of about 250kHz--all things otherwise being equal.
Mike...
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Similar Messages

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

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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.
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(Sorry no Labview "brag list" so far)

Changing size and resolution with pl/sql

Hello,
does someone know if it is possible to change the resoultion and size of an uploaded image with pl/sql?
we want to upload an image over a webform and want to save it in the database, but before saving it, we want to change the resolution to 72 dpi. Our webapplication is a PL/SQL application and we are using oracle application server 10G, release2.
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Hi,
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HTH.

Highly disappointed and demotivated with Moderator's Act

Hi SCN,
Today Morning, I have got a notification on Moderator rejection of one of my motivational blog. For your reference :--
I was really shocked to see my blog got rejected after almost 2 years. I am not sure whether a moderator has gone through my blog completely along with fellow SCNer's comments. They have all expressed that they are motivated with my blog. In what way, my blog is ruining SCN culture and standards??
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Regards,
Suman

Hi Moshe Naveh ,
I would like to thank you for considering my request and releasing the blog . I appreciate your timely action.
@ Matthew Billingham ,
If I hadn't brought this concern today, my blog would have been hidden forever. Hope you are aware that we cannot control our emotions in certain events/incidents. I have asked Moderators, why it has been hidden.
Regards,
Suman

Problem (and resolution) with VI Server and Windows Firewall

I have recently implemented a version of the "Rendezvous" VI's that work over the network using the VI Server. Essentially, I wrote wrapper functions using "Call by Reference" for each of the VI's in the Rendezvous palate. I have an isolated subnetwork that all the machine are on (i.e. no internet, no DNS). The VI's work great on the local machine, or on networked machines when the Windows Firewall is turned off. However, when the Windows Firewall is on for the CLIENT machine, I get an error trying to access the VI Server on the Server machine. My understanding is that the windows firewall is inbound only? Regardless, I entered "exceptions" for all possible ports that LabVIEW should be using as listed in:
http://digital.ni.com/public.nsf/allkb/2ED134294484FB4E86257212005951DA
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Regardless, I found out another solution: include entries for all the client machines in the "hosts" file on the server machine.
This windows version of the "lmhosts" file resides at: [WINDOWS]\system32\drivers\etc
The "lmhosts.sam" file contains documentation on entries in the "hosts" file.
Incidentally, I also discovered that client entries in the "hosts" on the host machine drastically reduce timeouts associated with using the datasockets server on networks with no dedicated DNS. (I believe datasockets tries to do a reverse lookup and has to time out, with the hosts entry the lookup executes immediately)
Enjoy!

I have no entries in the "hosts" file on the client side. I only made entries to the "hosts" file on the server. That's the weird part! The client firewall blocks the connection unless the server has and entry for it in the "hosts" file!
I haven't really used the shared variable that much and haven't tried it. If I had to speculate, I would guess that it may affect it similarly. It did seem to have a positive effect in shortening the long duration timeouts that I was having with datasockets.

High frequency power measurements

Hey,
I'd like to know if there are developments in measuring electrical high frequency signals with labview without using an extern power analyser. At the moment i'm using a yokogawa power analyser but i'd like to know if it's possible to log HF signals without the help of a power analyser... Are there NI products on the market for this purpose?
Thx,
Andy

Hello,
In the case of frequencies up to 200 KHz, NI can provide several solutions using the 'standard' data-acquisition boards or digitizers (scopes), from a low to very high accuracy solutions.
A good solution can be one of the high speed M-series boards (PCI-625x). These boards have up to 32 multiplexed channels with a resolutions of 16-bit at a speed of 1 MS/s (500 KHz).
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The best solution is to use a digitizer (scope). Also here a lot of possibilities going from low to higher bandwidth and resolution.
The most flexible is the PXI-5922. A 24-bit digitizer if you sample @ maximum 500 KS/s. This board only exist in the PXI platform.
Then NI has 8-bit digitizers (normal resolution for scopes) from 15 till 125 MHz bandwidth. If you need a higher resolution they have solution up to 14-bit (very high for scopes) @ 100 MHz.
Please give your local NI Office a phone call.
They have technical engineers who can discuss your needs and provide you a solution.
Best regards,
Joeri
National Instruments
Applications Engineering
http://www.ni.com/ask
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"Accept the Solution" if your question is answered!

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
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bitrates and can be used to publish "audio only" stream
also.

Circular and oval cropping at set size and resolution?

I know how to use the M tool to create circles and ovals and i know you can set that to certain dimensions, but that doesn't do everything I need.
How do you crop circles and ovals out of a photo, at a set size (for example, a 1 inch circle ) at a set resolution for printing? What I need to do is crop circular and oval images out of a photo, say at 250 dpi, then paste them onto a blank white page for printing.
So if I've got let's say a photo that's 14x10 inches at 300dpi, I want to be able to go in, crop out an oval or circle, with as much or as little of the photo that I can or want to, setting that automatically to a certain dimension and dpi, then paste it into a blank white page I've already created at that same d
When finished I'd have maybe 20 or 30 images on a page that I can flatten all the layers and print.
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You can make an action and use it as one step automation to achieve that on an initial selection.
Step by step instructions:
With the Elliptical Marquee Tool, make the desired selection on a image.
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From the Image menu, choose Crop.
From the Selection menu, choose Inverse (Ctrl+Shift+I)
Press the d key on your keyboard to reset the foreground/background color swatches.
Press Ctrl + Delete keys on your keyboard to fill with white.
From the Image menu, choose Image Size (Ctrl+Alt+I), make sure the Resample Image is checked, and in the Document Size section enter the desired dimensions and resolution and press OK.
In the Actions Panel press the Stop Recording button.
Now you can copy or drag the image to another image.
For the next image make the oval selection, go to the Actions panel, select the actions you created above, and press the play button. You can also create a keyboard shortcut in the action's property accessible by double clicking the action.
The creation of this action assumes that in the final image you will be composing oval images on white background without overlapping their rectangular bounding boxes. If you plan to overlap them then the action must be modified to make the image a transparent layer and delete outside the oval instead of filling with white.

Record and Playback performance goes down at high frequency

Hi,
We're testing record and playback using USRP-2920( LV 2013sp1, NI-USRP 14)
To test it, we downloaded record and playback example code.
Signal source is a function generator outputting 6 MHz bandwidth 8 VSB modulation signal.
USRP Rx parameters are center = variant / gain = 0 / IQ rate = 25MHz and Tx parameters are center = same as Rx center / gain = 0 / IQ rate = 25MHz
The problem is... in low carrier frequency like 70MHz, quality of playback signal is great.
But in high carrier freqency like 2.2GHz, SNR and signal power dropped significantly i.e. they tend to drop as carrier frequency goes high.
And the strange thing is as carrier frequency is increased, a small peak on the center is increased as well.
Please check the attatched file to see the tendancy.
So.. my question is why is this tendancy occures?(we tested another USRP and the result was same as before)
and what should we do to reduce this effect?
Regards,
Youngmin
Attachments:
record and playback results.xls ‏469 KB

Hi,
I suggest a couple of things:
NI USRP 2920 is a non-calibrated device. So setting a gain value of 0 at different frequencies could mean a different actual gain. So try increasing the Rx recording gain (on the USRP) in cases where you observe low SNR. Similarly Tx is not calibrated.
Is the signal recording done with cables or over wireless medium ? You can try to eliminate any spurious signals if you use SMA cables while recording.
I think the power at the center of the spectrum is the DC offset. You may refer to the DC Offset/LO leakage section in the best practices section here http://www.ni.com/white-paper/13881/en/
Thanks.

I have an imac 27 inch O SX 10.6.8. using iphoto 11 Version 9.1.5. I have scanned some photos at very high resolution with each photo being about 45MB. They're saved to desktop. How can I reduce the size of the scanned photo's they are crashing iphoto

I have an imac 27 inch O SX 10.6.8. using iphoto 11 Version 9.1.5. I have scanned some photos at very high resolution with each photo being about 45MB. They're saved to desktop. How can I reduce the size of the scanned photo's they are crashing iphoto.

What format are they? Tiif? Jpeg? You can compress them with a lot of apps - including Preivew and just about any graphics editor out there. I'm not sure that 45mb would crash iPhoto thogh, are yo sure that's the cause? I know that some folks have mentioned pixel dimensions causing issues, as can color profiles.
Regards
TD

Problems with displaying high frequency sine wave

Hi all,
I don't why LabVIEW has problem with high frequency display.
Someone plzzz explane me how to see a better grapth on grapth?
check this function waveform generation.vi in examples go to search and type "waveform"
set the feq to 1k.
Thanks and regards

I think that this is related to LabVIEW, but more basically to the Shannon theorem : if you want to describe a periodic function, you need to take enough samples. First, expand the x scale to see a delta t of 0.001 s (ie a period of your 1000 Hz signal). Remeber to set the autoscale property on OFF. Then go to "sampling info" and increase the sampling frequency. See the result...
CC
Chilly Charly (aka CC)
E-List Master - Kudos glutton - Press the yellow button on the left...

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 sound with K8T Neo-FIS2R

Hello!
I have the MSI k8t neo-fis2r mainboard with bios v 1.6 and sometimes it makes a horrible high frequency sound and I cant figure out why.
My system are:
amd 64 3000 cpu and
Corsair Value S PC3200 DDR-DIMM 512MB Unbuffered, Non-parity, 64Megx64, CL2.5
My other components does not cause the sound (that I have found out by testing).
I wonder if the ram causes the sound? Can you please help me. The sound is so bad that I cant use my computer. It only appers during heavy system load, and not in windows. It has nothing to do with my video card (because I have tried with several different cards). My bios settings are default values + cool and quit enabled. I have the core center installed so the progam controls the cpu fan.
I really hope someone can help me.

The sound does not come from the speaker and I dont think it comes fom the cpu fan either. I think it comes from the motherboard, ram or the cpu. When I dont use my mouse it is quit but when I clik it makes this sound. Can it be that I have to set all values in bios for ram etc. manually instead of automatic?
When it comes to other electrical sources I have a TV standing 0.5 meter from the computer. Could thins cause the problem? I did not have the problem with my old motherboard which was a MSI K7T Turbo2.
The sound usually appers when I am benchamarking my system. For example 3dmark 2004. Because of this I thougt there was a problem wiht my vga card but after a changed to a new one...the situation was just the same.

Performance issue with high CPU and IO

Hi guys,
I am encountering huge user response time on a production system and I don’t know how to solve it.
Doing some extra tests and using the instrumentation that we have in the code we concluded that the DB is the bottleneck.
We generated some AWR reports and noticed the CPU was in top wait events. Also noticed that in a random manner some simple sql take a long time to execute. We activated the sql trace on the system and noticed that for very simple SQLs (unique index access on one table) we have huge exec times. 9s
In the trace file the huge time we had it in fetch area: 9.1s cpu and elapsed 9.2.
And no or very small waits for this specific SQL.
it seems like the bottle neck is on the CPU but at that point there were very few processes running on the DB. Why can we have such a big cpu wait on a simple select? This is a machine with 128 cores. We have quicker responses on machines smaller/busier than this.
We noticed that we had a huge db_cache_size (12G) and after we scale it down we noticed some improvements but not enough. How can I prove that there is a link between high CPU and big cache_size? (there was not wait involved in SQL execution). what can we do in the case we need big DB cache size?
The second issue is that I tried to execute an sql on a big table (FTS on a big table. no join). Again on that smaller machine it runs in 30 seconds and on this machine it runs in 1038 seconds.
Also generated a trace for this SQL on the problematic machine:
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.00       0.00          0          0          0           0
Execute      1      0.00       0.00          0          0          0           0
Fetch        1    402.08    1038.31    1842916    6174343          0           1
total        3    402.08    1038.32    1842916    6174343          0           1
db file sequential read                     12419        0.21         40.02
i/o slave wait                             135475        0.51        613.03
db file scattered read                     135475        0.52        675.15
log file switch completion                      5        0.06          0.18
latch: In memory undo latch                     6        0.00          0.00
latch: object queue header operation            1        0.00          0.00
********************************************************************************The high CPU is present here also but here I have huge wait on db file scattered read.
Looking at the session with the select the AWG_wait for db scattered read was 0.5. on the other machine it is like 0.07.
I though this is an IO issue. I did some IO tests at SO level and it seems like the read and writes operation are very fast…much faster than the machine that has the awg_wait smaller. Why the difference in waits?
One difference between these two DBs is that the problem one has the db block size = 16k and the other one has 8k.
I received some reports done at OS level on CPU and IO usage on the problematic machine (in normal operations). It seems like the CPU is very used and the IO stays very low.
On the other machine, the smaller and the faster one, it is other way around.
What is the problem here? How can I test further? Can I link the high CPU to low/slow IO?
we have 10G on sun os with ASM.
Thanks in advance.

Yes, there are many things you can and should do to isolate this. But first check MOS Poor Performance With Oracle9i and 10g Releases When Using Dynamic Intimate Shared Memory (DISM) [ID 1018855.1] isn't messing you up to start.
Also, be sure and post exact patch levels for both Oracle and OS.
Be sure and check all your I/O settings and see what MOS has to say about those.
Are you using ASSM? See Long running update
Since it got a little better with shrinking the SGA size, that might indicate (wild speculation here, something like) one of the problems is simply too much thrashing within the SGA, as oracle decides "small" objects being full scanned in memory is faster than range scans (or whatever) from disk, overloading the cpu, not allowing the cpu to ask for other full scans from I/O. Possibly made worse by row level locking, or some other app issue that just does too much cpu.
You probably have more than one thing wrong. High fetch count might mean you need to adjust the array size on the clients.
Now that that is all out of the way, if you still haven't found the problem, go through http://oracle-randolf.blogspot.com/2009/02/basic-sql-statement-performance.html
Edit: Oh, see Solaris 10 memory management conflicts with Automatic PGA Memory Management [ID 460424.1] too.
Edited by: jgarry on Nov 15, 2011 1:45 PM

Data acquisition and frequency generation togather with PCI-6251 and LV8.2

Hi friends,
I am a new user of Labview. I am using LB8.2 with PCI-6251 .
I have to generate frequency and then measure the data and then for next frequency and so on.
i know that for this i have to use looping and that is not a problem. The real problem for measurement is to identify whether the frequency is been generated. if yes then measurements starts otherwise it should wait until it started. then after finishing the measurements send a signal to generator for changing the frequency and amplitude.
Now these two things {generation and measurement} togather are not working correctly for me. so i make 2 diff file, one for generation and other for measurements <by modifying the examples>. I can run both file togather and it works. But it need lots off effort and time. I have to measure from 10Hz to 1000Hz in 2Hz frequency step and i cannt leave in between .
can anyone help me how to syncronize these two togather .
Trying to attatch. both the files here ..
main_v1.1.vi --> for Measuring
Oscilloscope.vi --> for waveform generation
Attachments:
main_v1.1.vi ‏150 KB
Oscilloscope.vi ‏37 KB

Hay thnx dude..
I found the example and now it works
once again thanks a lot

High frequency and resolution with 6036E

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