Common mode rejection ratio

I am using the PXI-4461 and the sound and vibration toolkit. I need to test the common mode rejection ratio of Amplifier.
Can sound and vibration toolkit do that? I can find the same phase input???

In sound and vibration toolkit, output AO0 or AO1 can select the follows setting: differentital, pseudodifferential, RSE. The setting indicates one output. That means AO0 can set to differentital, pseudodifferential..... and AO1 can set to differentital...... too. I want to test the CMRR of the Amplifier, and I certainly only use one of the output to test.
When the output signal is set to differentital, voltage of AO(+) and AO(-) are reverse phase. and when I want to test CMRR, I must set voltage of the AO(+) and AO(-) to same phase. The AO(+) and AO(-) is the two voltage of the same output.
The trouble of test CMRR is I don't know how to set AO(+) and AO(-) to same phase.
Thanks for your help!

Similar Messages

Common moder error NI TB-9214

Hi all,
I'm used NI 9214 to measure thermocouple reading which connected using NI TB-9214. When I connect thermocouple and then taking a measurement for each channel (connect one by one for the entire channel), the measurement is fine. But when I connect a thermocouple at a few channel, some channel give a common mode error. I don't have an idea why this error occured and how to solve it. Please advise. Thank you.

The first code block contains my Xorg.0.log however I just tryed modprove nvidia and recieved FATAL: Module nvidia not found. which I discovered was solved by someone here https://bbs.archlinux.org/viewtopic.php?pid=961852 however when I tryed to do a pacman -S nvidia nvidia-utils I get a unresolved confilict with nvidia-304xx-utils which after trying to remove with pacman -Rs shows dependencies with cario, Im not sure how far back I should start removing things to solve this conflict or how to go abouts solving it
+++++++++
Update: Solved
+++++++++
I did some more looking and found I could force the uninstall of nvidia-304xx-lts with pacman -Rdds nvidia-304xx-lts and after revisiting the Nvidia page on the wiki for the dozenth time I started thinking maybe I needed nvidia-304xx oposed to the lts release as google as kindly pointed out lts is long term support and maybe my kernel was not lts and thus conflicting. This turned out to be the case, after removing the ofending lts version of the driver, replacing with the correct nvidia-304xx , another nvidia-xconfig and reboot followed by modprobe nvida and startxfce4 my wounderfull xfce is now running as I type this messsage in firefox. Thank you for you help, as you asking about the modprobe output caused the chain of events leading to the success.
Last edited by meschael (2014-09-18 04:15:30)

What is the common mode range of the 6033E Daq Card?

I'm reading the voltage accross a 10 ohm resistor in
Differential mode. There is 1 AMP DC current
flowing = 10 volts.
When the UUT fails, the voltage on one side of the
resistor could go as high as 50 volts.
That's why I would like to know if the common mode
voltage of the DAQ is withing 50 volts.
thank you...
\\carlos_diaz

For DIFF mode, V+ and V- in have to be within +/-11V of AIGND. You'll probably have to go with NRSE.

Squeeze Mode - Aspect Ratio

This is what I am doing...
I have multiple video signals coming into a mix board. The mix board goes into my computer. I am recording the signal into FCP. All the my cameras are shooting in squeeze mode to fake the 16:9 aspect ratio.
This is what I want...
I want FCP to automatically adjust the aspect ratio so I don't have to render the video after the session is over.
Is this possible?
What do I need to do?
To answer these questions do you need more details?

That's right. Anamorphic is squeezed video. This is standard in standard definition. Depending on the format it goes to, there is a setting that lets that program/player/whatever know that it is widescreen and should be stretched out. With HD it is true widescreen. However, if you want to go to the Internet or something where it's displayed on a computer, it should be set to it the equivalent in square pixels, which is 853:480 (sometimes 854 is used when a program can't read an odd number). Quicktime will also recognize it as 720:480 widescreen if you output it correctly for the same reason stated above, it's marked that the program has to stretch it when displayed.

T530 Airplane In-Seat Power Mode = reject power adapter

Hello,
I have a T530 quad core, which means I need the 135W power adapter. I was flying yesterday and my seat had power, so I figured I would use the "Airplane In-Seat Power Mode" function on Power Manager to avoid tripping any breakers on the airplane. However (and I've tried this at home as well on AC mains), choosing the airplane in-seat power mode doesn't seem to result in the advertised "adjusting charge rate and cpu" - instead it just causes the laptop to not charge at all and say this:
"This AC adapter may not provide enough power to your Lenovo computer. Please reconnect the proper AC adapter."
Of course... it is the right adapter... and switching off Airplane Power Mode makes it start charging normally again immediately.
I have the BIOS update needed that says it enables this feature (1.12), and Power Manager 6.32.
Has anyone else tried Airplane In-Seat Power Mode and had it work, or can anyone from Lenovo comment on this?
THANKS!

brillat wrote:
choosing the airplane in-seat power mode doesn't seem to result in the advertised "adjusting charge rate and cpu" - instead it just causes the laptop to not charge at all
The fine print on at-seat-power for many airlines specifically excludes "battery charging" as a permitted use, so it may well have something to do with that restriction.
Will there be enough power for my device (how many watts can it handle)?
Most airplane power systems are limited to approximately 75 Watts of power draw per seat. This means that a new 17" laptop, with a power-hungry processor, might not get enough juice to operate. Sometimes the laptop will know not to charge the battery and will just operate via the power, but other times the laptop won't work at all, or will work for a short period of time before tripping the power circuit. You can try taking your battery out all together, or buy a smaller laptop.
The SeatGuru power converter reviewers recommend removing the laptop battery before plugging the device into the EmPower unit. The laptop should then run on EmPower. Often, about one hour to 30 minutes before the end of a flight, the EmPower system will be as shut-off, and the laptop will abruptly lose power. (Make sure to save your work!)
Will my battery charge while I'm plugged in?
Don't count on it. Again, because of the limited amount of power draw per seat, it is possible that your laptop won't get enough power to both operate and charge. Some airlines, like Continental Airlines, specifically state that battery charging is not allowed and ask you to remove your rechargeable battery from your device.
- http://www.seatguru.com/articles/in-seat_laptop_power.php
Cheers,
Bill
I don't work for Lenovo

Audiobox usb interface won't mount on MacBook Air

PreSonus AudioBox USB (2in/4out) when attached to either USB on mid 2013 MacBook Air 11, won't show up in garage band, garage band preferences, apple audio system preferences, apple midi system preferences or even in the 'about this mac' system report. The device is totally unrecognized and supposed to be totally compliant plug and play. I'm runnin OS 10.9.1 with all updates. The AudioBox interface shows red power light and a light on the 48V phantom power button. All cables are good, Microphone functions and MacBook air is connected to a power supply. (Macbook, condenser microphone, AudioBox and all cables are new.) Any experience with this out there?

Yes, Id return it and either:
get the Roland UA-22 Duo-Capture EX
or the Focusrite Scarlett 2i2 USB
WHAT mic?
The best idea is to drop that noisy and hissy squawk box and get a ZOOM H6 which has USB interface with MORE options, LESS noise, and far easier to use
phantom power from the H6 is from 4 AA batts, and not via USB. (have and use same myself) with these Mics:
The unit youre using is getting 48V phantom via USB, which depending on the Mic, often stinks.
Microphone Preamp
Type
XLR Female Balanced
Frequency Response (±3.0 dB)
14 Hz to 70 kHz
Input Impedance (Balanced)
1200Ω
THD+N (unwtd, 1 kHz @ +4 dBu Output, Unity Gain)
< 0.008%
S/N Ratio (Unity Gain, Ref. = +4 dBu, 20 Hz to 22 kHz)
> 95 dB
Common Mode Rejection Ratio (1 kHz, 55 dB Gain)
> 45 dB
Gain Control Range (± 1 dB)
0 dB to 35 dB
Max Input Level (Unity Gain, 1 kHz @ 0.5% THD+N)
-3 dBu
Phantom Power (±2 VDC)
+48 VDC
Instrument Input
Type
¼"
TS Female Unbalanced Input Impedance
0.5 MΩ
Line Outputs
Type
¼"
Balanced Output Impedance
51Ω
Headphone Output
Type
¼" TRS Active Stereo
Maximum Output
60 mW/Ch @ 60Ω Load
Frequency Response (±1.0 dB)
20 Hz - 30 kHz
MIDI I/O
Type
Dual 5-pin Female DIN
Digital Audio
ADC Dynamic Range (A-wtd, 48 kHz Sample Rate)
105 dB
DAC Dynamic Range (A-wtd, 48 kHz Sample Rate)
105 dB
Bit Depth
24
Reference Level for 0 dBFS
+4 dBu
Internal Sample Frequency Selections (kHz)
44.1, 48
Power
USB Bus-powered

How to test CMRR with pxi4461?

I have a PXI-4461 and the sound and vibration toolkit.
How can I test the amplifier's CMRR(common mode rejection ratio)?

The problem is not measuring voltage, but how PXI-4461 to generate the right signal to test CMRR, Pls find the attached picture.
Thanks in advance!
Attachments:
æ°å»º ä½å¾å¾å.PNG ‏9 KB

Another LM324 SPICE Model error

LM324 "generates" negative voltage in schematic with single power supply voltage.
Attachments:
IdiotTest#2.ms12 ‏105 KB
Test #2.jpg ‏214 KB

Hi,
The model you selected was made by Motorola and unfortunately, when this model was imported into Multisim, the comments to show what this model was designed for was removed. Some models will not work with single rail. I was able to find the library where this model came from and base on the comments, this op-amp model was designed for the following:
- Positive and Negative Slew Rate
- Quiescent Power Dissipation
- Maximum Positive and Negative
- Output Voltage Swing
- Input Bias Current
- Open Loop Voltage Gain
- Unity Gain Frequency
- Common Mode Rejection Ratio
(CMRR)
- Output Impedence (ac and dc)
- Output Short Circuit Current Limit
You can find the original model from here:
http://www.gunthard-kraus.de/Spice_Model_CD/Vendor%20List/Spice-Models-collection/motoramp.lib
The opemp have several models, try the one from TI
Tien P.
National Instruments

45 Hz noise

I trying to make an acoustic (pressure) measurement using the PXI 4496 and I don't fully understand why my signal looks the way it does. Here is a graph of the time signal with 3 channels and also the power spectrum of the pressure channel.
http://forums.ni.com/ni/attachments/ni/100/1989/1/acoustic_channels_test_FP.png
the white trace is the pressure channel, the red is a IEPE accel. and the green is a disconnected channel and both tranducers have excitation to them. However, neither transducer is seeing any changing phenomena. That is, the sensors are just sitting there and you can see a large ~45 Hz signal on the pressure channel. For this measurement, I'm using a kulite XTE-190 transducer that has a FSO of 100 mV and you can see that I'm getting signal at 25% of the FSO without doing anything. My wiring configuration goes like this. A 4 conductor shielded cable brings the 10V floating DC excitation to the transducer using 2 conductors and the bridge output of the transducer is brought back to my PXI 4496 using the other 2 conductors. Right now I don't have the shielding tied to ground anywhere.
Message Edited by caz on 02-26-2009 01:55 PM
Attachments:
acoustic_channels_test_FP.png ‏16 KB
acoustic_channels_test_FP_time.png ‏15 KB

Hi Caz,
As Jason mentioned, it's a good idea to ground
your shield. But only ground it in one place: at the transducer, or at
the device. If the shield is not tied to anything then it is floating
and essentially does not function as a shield anymore.
You
have a point about common mode rejection. It does appear that the 4496
is not rejecting the common mode signals in the excitation signal. I'm
curious about the excitation signal you are using. You said it's a
noisy DC source. Is it stepping? The AC-coupling filter on the 4496 has
a settling time in response to DC steps. If you were to look at an
acquisition on a 4496 during a step it would look like a spike with an
exponential decay curve afterward, kind of like what you have in your
acquisitions. It would be great if you could get a hold of a DC-coupled
instrument to monitor your excitation and your bridge output and post
that so we could take a look at it.
I'm also curioius about your configuration.
1) Is your excitation source floating?
2) Could you draw a diagram showing where you are connecting signals from your bridge
a) When you have the huge noise in the measurements of the 4496
b) When you are doing the differential measurement with the 4496
3) What is the DC voltage present on the negative (shell) of your 4496 inputs during these acquisitions?
DanielConditioned Measurements Hardware

Measuring current on a Voltage Rail 10V

I am attemting to measure the current and voltage on a 15V power rail. (Here is a copy of my circuit attatched) I am using a USB-6225 DAQ and Lab View,
I have my device under test connected to a power supply. I have connected two differential channels to the DAQ, one for the current and one for the voltage.
I understand that the DAQ can not handle more than 10V so I use a voltage divider to half the voltage. When I run the measurements, the current reported is incorrect. It shows 10A when it should be about 500mA.
When I reduce the voltage on the power supply to 10V, it all works fine, so I am guessing its got something to do with the 10V limit.
Please can you advise how I can connect this up correctly?
Solved!
Go to Solution.
Attachments:
DAQ Set Up.jpg ‏29 KB

R(Sense) should be within 10 volts of the DAQ chassis. Thats all the common mode rejection you are likely to have on a DAQ device. (But check your device specification sheet ---- don't trust me RTFM!)
if you do not have a common "Ground" between the DAQ device and the supply you are monitoring you will need an opto-coupler (But any first year EE student could tell you that)
As an Asside.: Who the hell ever started the convention of stuffing R (sense) on the + side of a circuit anyhow? Use a regulated supply with "Remote sensing" if you really care about the DUT power consumption.
Jeff

How can I start install the design on FPGA

hi ,
i design a system on the labview 8.2 thats detect some parameter of the ECG signal , now i wnat to install the design on the FPGA kit
kown the input signal is real time ECG signal .
how can i start doing this ?
what the needed informaton to do that ?
thank you

Hi - I just want to clarify that National Instruments does not make any signal conditioning modules or other products that are designed for direct connection to a human subject (we don't design or certify to the required medical safety standards). Our products are often used in conjunction with amplifiers or signal conditioners that are designed for these applications that have outputs that are filtered, isolated, and amplified and are ready to be digitized by a DAQ board or other NI product.
If used on animals, these safety concerns are often not as big an issue, but you still need a specialized signal conditioner that has a relatively high gain and balanced differential inputs (with high common-mode rejection) to acquire a good, low-noise ECG signal. This is similar to a thermocouple type input module, but with more bandwidth than a typical thermocouple module and AC coupling.
Bottom line: you really need to use a specialized biosignal amplifier that has a single-ended analog output to connect to NI DAQ boards or FPGA boards.
Steve J.
National Instruments
Visit the NI Biomedical User Group at:
www.ni.com/biomedusers

In normal view, half the page disappears off right of screen. in full screen this does not happen. what can be done to correct the screen ratio for normal screen?

version 5 loaded on windows 7. all went well for a while. one day while using, ratio of normal screen doubled in width; i.e. half the page disappears off the screen to the right (on a wide screen). when full screen mode applied, ratio is fine. it only happens in normal view, which is the usually prefered option. I cannot determine any means within the program to resize the normal screen. nothing else is affected, only mozilla firefox in normal view. not that when program is opened from keyboard the page is correct for a moment, then enlarges the width with 1/2 page dissappearing.

This issue can be caused by the Babylon Toolbar 1.1.8 extension
*https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes
Start Firefox in <u>[[Safe Mode]]</u> to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).
*Don't make any changes on the Safe mode start window.
*https://support.mozilla.com/kb/Safe+Mode

Reject workflow

I may be crazy, but I think the "Reject" UI behavior used to be different.
When I have the Browser on one screen, and a full screen preview on the other, I'd like to quickly reject photos and have Aperture move to the next photo. I have a pretty high reject ratio, and currently I have to reject, hit right arrow, hit reject, etc.
I swear Aperture used to behave differently. Maybe it was back in 1 or 1.5, but I seem to remember being able to repeatedly hit reject to quickly cull my photos.
Does anybody know of a way to make it behave like that? thanks

The Command Editor is a bit Yoda-like -- very powerful, laconic, and inscrutable.
With the Command Editor open, click the on-screen representation of the 9-key.
In the "Key Detail" pane, click the oval-ended gizmo "Reject" and drag it from the "No Modifier" spot to the "Command" spot. In like manner, move the "Reject and Move to Next Image" gizmo to the just vacated "No Modifier" spot. Then move the "Reject" gizmo to the "Control" spot. Click "Save" and then close the Command Editor. Try your newly re-assigned keyboard shortcuts.
If you hadn't already created a custom Command Set you will be prompted to do so (you can't alter the default set).
The User Manual contains a [thorough section describing the interface|http://documentation.apple.com/en/aperture/usermanual/index.html#chap ter=27%26section=4%26tasks=true], but not much on how to actually use it. You may find it helpful. Their instructions are different than those I've given you above.
"Gizmo" is not official Aperclature.

Dock unavailable in full scrren mode?

I'm finding that the osx dock becomes unavailable when I'm editing in full-screen mode. Apple has suggested that this should be the most common mode for most uses, and yet if I have to toggle out of it to get to other apps (like checking mail, etc), it seems annoying. Anyone else noticing this?
dual 2ghz g5 Mac OS X (10.4.8)

I for one love that the dock gets hidden: more space for photos.
however, you can move your dock to the side: if you have a dual display setup, the second display can be made to keep showing the desktop in F mode.
if you don't have a dual display setup, consider it. it's a revolutionnary change: you'll never look back!!!!!

E-mail password rejection on Mac

I am adding my experience to the long list, just so that BT knows the problem is widespread and continuing. Yesterday and today, so far, I suddenly lost my BT Yahoo mail on my Mac with the now common password rejected message. I have no time to fix it so will use webmail meantime, but it just hammers another nail in the BT coffin.

Until April 2012 there were enough threads on password rejection to knit a large sweater but then the moderator closed the forum saying all was well. It isn't. I have been unable to access my bt mail since March except by logging on to webmail after which macmail behaves correctly for about 1 hour. Wasted £30 on a premium BT help service on this matter. Very nice guy but perplexed! This issue is not dead. I had the same issue with my iphone which was resolved in an Apple store. Is there now a fix for this utterly irritating situation? It does BT no credit whatsoever. Any chance of reclaiming my lost hours and £30? I think I know the answer to that one.

Common mode rejection ratio

Similar Messages

Maybe you are looking for