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79 Threads found on edaboard.com: Measure Input Noise
Hi, I am trying to measure AC rms voltage using PIC microcontroller. I have attached the circuit for measurement. I am connecting a 3V step down transformer out to the input of the circuit.The feedback capacitor has been added to reduce the noise, but I am getting noise if I add this. This is getting (...)
Do as per FlapJack. We measure noise with 50 ohms system. Oscilloscope : 50 Ohms input, DC coupled, Offset adjusted. lower voltage/division capacity like 2mV or 3mV/div, try with 20 Mhz BW limit for better performance., Cable : RG174 cable(rf174-04sp3-04sp3-2000 these cables are avbl fom samtec) has very small core, useful in soldering (...)
I can understand RMS is like the average, not the instaneous value. but why sqaure it? why not just plain RMS. or to 3rd, 4th power. why square?
Hi, I'm having difficulty verifying my test for measuring noise Figure of an assembly using a spectrum analyzer set for noise spectral density. Essentially I'm trying to measure noise figure by loading the input to 50ohms, having the device on (with LOs) and measuring the NSD at the output. I can (...)
Hey all, I've done noise analysis on several signal paths now both measured with a spectrum analyzer and simulate in LTspice. I either measure or calculate the output noise in the units of nV/sqrt(Hz) and then refer it to the input by backing out the gain of the path. Only issue now is I'm working with (...)
With a wave analyser (audio spectrum analyser), you can measure the amplitude of each harmonic and then mathematically sum them to get a total figure. Frank
you might be confusing different concepts. For example, to get a 1 Hz resolution, you need to measure for a 1 second time period for "normal" frequency counters. There have been some commercially manufactured frequency counters that had high frequency internal oscillators inside (500 MHz for example) and your input waveform gated the counting of
1) yes, so long as you do not overdrive the input with too much RF power 2) no, but you can measure the "residual" phase noise
Hello all! I am trying to perform some simulations on a TIA circuit on Cadence Virtuoso. In particular I am interested in plotting the BER vs input power graph, however I don't know any method to do so. For a particular input power I could measure the output swing it produces and divide it by the the output integrated (...)
I am using spectre to measure the noise performance of my schematic with spectre in Cadence . I wonder how the software to calculate the noise factor with the input noise and output noise . The simulation results show that noise factor doesn't equal to output (...)
The bottom limit is defined by noise. If you measure a DC voltage, check the opamp 1/f noise and use a low-pass filter to limit noise bandwidth. You also have to define the input impedance to refer the noise power and voltage. The higher the imedance, the higher the noise (...)
Hi all Can I use the HP 8970B noise Figure Meter to measure the NF of an amplifier at 2-3MHz?
Just measure the noise at the output node of the device. If the device is in the middle of the circuit then you will have to measure the input noise and output noise, and subtract them to get the noise of the device.
IP2 and IP3 (input or output) are more related to the system design. As a stand alone device, for an LNA doing a simple P1dB measurement will give you information about the linearity of the device. Most of the time for LNAs is valid the rule: IP3(dBm) = P1dB + 10dB. To get this equation valid, the LNA should use proper bias filtering.
As said, I want to measure the input and output referred noise of an amplifier in practice. I have some thoughts and want to share them to see if they hold true. Assume a single ended input, single ended output amplifier. Should i do it like, 1) short the input 2) measure the (...)
Put a 10dB attenuator in between the oscillator and spectrum analyzer. Reduce the RBW to measure the harmonics reliable well above the noise floor. Check if the harmonics are still at the same level (~50dBc).
Hello all, I am designing a low noise amplifier for low power applications. I have a question. I know we usually use SP analysis to measure the performance of the LNA which tells us about gain, reverse isolation, input reflection etc. The problem is , I get different values of gain from noise analysis, ac analysis and (...)
I think the noise simulation doesn't need any input nor output sources in order to introduce/measure noise: you may remove I7, C0, V1, L1, IPRBB0 and L0 (which is a cap). Just refer the resultant output noise @ vo to the input noise @ the drain-to-source connection node, (...)
I have no idea, it is an ibm x60s, you say the dynamic range would not be enough to measure such things? Yes, by many orders of magnitude. The A/D chip in your computer's sound card is specified with 90dB dynamic range. Amendment: it seems that high qu
Hi everybodoy, I've got a doubt concerning the use of noise simulation in LTSpice. As far as I know, the input current noise density (inoise in LTspice) is the equivalent noise at input coming from every noise source in the circuit. I'm dealing with one schematic (...)