The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
1answer
32 views

Nyquist Sampling rate

We have \$z(t)=\cos(100πt)\cos^2(500πt)\$ . Find Nyquist sampling rate. Well, I know that \$f_s=2f_{max}\$. My main problem is that I am not entirely sure if I could re-write the above signal as: ...
1
vote
3answers
68 views

what is the difference in u-controller processor sampling frequency and the z-domain conversion sampling frequency?

I have observed a bit confusing behavior of my system response (or may be i am missing something). I have a transfer function in S domain converted to Z domain with a 1kHz sampling frequency at the ...
0
votes
0answers
50 views

ADC and Pre-Amp Suggestion for RBpi

I want to receive VLF signals (between 15kHz to 30kHz) with my RBPI. So I can found only this antenna: Miniature Very Low Frequency Antenna ANTM1. This miniature 6 inch long antenna can be ...
1
vote
1answer
83 views

Weird samples from SAR ADC

I am playing around with some SAR (Successive Approximation) A/D-converters. I have made a test circuit where I have a 16-bit DAC from Texas Instruments (R2R-based) and an 16-bit SAR ADC from Analog ...
0
votes
0answers
14 views

Activate Single Trigger Mode on SMIQ06B's Arbitrary Waveform Generator

I am a research student looking for a way to program or add a single trigger mode to SMIQ06B's (signal generator from Rohde & Schwarz) arbitrary waveform generator (SMIQB60). It only have 4 ...
1
vote
1answer
122 views

Connect VLF antenna to raspberryPi

I want to connect two VLF antenna (given below) to a RaspberryPi using it's GPIO ports with a MPC3008 ADC. Desired frequency range is between 3kHz to 30kHz, and MPC3008 supports 200,000 samples/sec ...
0
votes
1answer
85 views

Transfering audio data between two DSP's, clock sync problem

I have a system with two DSP modules. The audio is routed from DSP1 to DSP2 and then back to DSP1, which in turn immediately sends it to DAC. It's a high-quality stereo sound at 44.1KHz. This is a ...
-1
votes
1answer
97 views

pulse amplitude modulation

Im bit struggling with PAM question. I've been trying to solve this for few hours but I am stuck at the stage where I need to sample m(t). Could you please help me with detailed answers and workings. ...
1
vote
2answers
72 views

What does “two signals aliasing to each other” mean?

So I just read something that two signals are aliasing to each other. I know what a single signal is being aliased - that is when sampling rate is not higher than or equal to the Nyquist rate. But I ...
0
votes
1answer
76 views

Resampling with MSB operation

I'm new to verilog and HDL, so please be patient with me. In a code, I have an input variable clk, two input 16 bit samples, that are stored into ...
-5
votes
1answer
44 views

Understanding the concepts of sounds analysis [closed]

I'm trying to understand many concepts behind sound analysis. Here's what I'm trying to understand: What's sound & sound wave? What's sampling and hertz? And how to do sampling? (starting from ...
1
vote
1answer
549 views

why is this oscilloscope so cheap with a 20Gsa/s sampling resolution?

I've looked around this site but I haven't been able to figure out why this oscilloscope seems to have such a high sampling rate "Repetitive mode: 20GSa/S" and be relatively cheap: ...
0
votes
0answers
34 views

PCM codes. Which to choose

If a sampled voltage sits on the line between two steps of a pcm code which one do you chose? ie 0.75v with pcm give an equivalent value of 96 which lies on the line between 92 to 96 and 96 to 100. Is ...
2
votes
2answers
80 views

Understanding sampling rate and frequency of logic analysers

Below shown is the screenshot of the GUI for Saleae logic analyser http://www.saleae.com/logic I would like to know what is the meaning of "number of samples to collect" and "sample rate" ? As per ...
2
votes
1answer
63 views

How many periods of a periodic signal are required to properly determine magnitude?

I have a pure sinusoidal test function. I am trying to determine the magnitude of the response through my circuit very soon after powering up with circuit. If I am using a 1kHz test signal, I only ...
0
votes
2answers
74 views

Choosing Oscilloscope with appropriate bandwidth for Jitter analysis

Can someone give me a rule of thumb of choosing Oscilloscope with appropriate bandwidth for the Jitter analysis of clock signals? What device is highly preferable: spectrum analyzers, frequency ...
0
votes
0answers
39 views

How to prove sampling is energy preserving using Parseval's Relation?

I have a continuous signal, xc(t) which is bandlimited to =pi/T, and x[n] = xc(nT) are samples of this signal. I need to show there is a Parseval's relation between the original signal and the sampled ...
2
votes
4answers
277 views

Do digital Anti Aliasing filters exist for traditional ADCs?

I'm currently learning about Analogue to Digital Converters. From what I understand, aliasing occurs if the input signal being sampled has power above the "Nyquist frequency" of the ADC(Sampling ...
1
vote
3answers
97 views

Sampling resolution

I"m trying to buy a physiological measurements device. In the device spec they mention: Sampling freq: 2kHz Channel bandwidth: DC up-to 0.2*Fs Sampling Resolution: 24nV/bit My question is, what ...
3
votes
2answers
157 views

Sampling Theorem

$$x(t) = \frac{sin(2000\pi t)}{\pi t}cos(1000\pi t)$$ is sampled with sampling period \$T_{s} = \frac{1}{8000}\$, to obtain the sampled signal \$x_{p}(t)=x(t)p(t)\$, where \$p(t)= \sum_{n = ...
5
votes
2answers
272 views

Does Nyquist rate depend on the sampling rate?

The book Computer Networks by Andrew S Tanenbaum mentions the following (paraphrased): For a noiseless channel, Nyquist theorem states: Maximum data rate = \$2H \space log_{2} V \$ bits/sec ...
0
votes
1answer
226 views

Visualising data rate as square waves (Converting bits per second into hertz) for selecting ADC sampling frequency

I know that bits per second and hertz are two different units. This question will help me in designing an oscilloscope with proper ADC sampling frequency for viewing communication protocols. Just ...
-1
votes
1answer
101 views

Undersampling of a non periodic pulse signal

I am starting getting familiar with electronics, consider me as a newbie.. I am facing a sampling trouble with my DAQ system. I have a non periodical pulsed signal with a separation between the pulse ...
1
vote
1answer
112 views

Nyquist sampling rate with real and imaginary aliasing

I need to calculate the Nyquist sampling rate of the function \$x(t) = cos(6t)-sin(5t)\$. By definition the Nyquist sampling rate is the minimum value of \$\omega_s\$ that yields no aliasing ...
1
vote
1answer
50 views

Sampling phone line

I want to connect phone line to my PIC's ADC to sample signal changes without interfering the line. Human voice and DTMF signals are all under 4kHz level. So, I am hoping that any 18F PIC can do ...
1
vote
1answer
182 views

How can you recieve a 6 GHz signal with only 64MS/s ADC?

The Ettus Research Software Defined Radio B210 has a range of 70 MHz - 6 GHz, a Bandwidth of 56 MHz and its maximum ADC rate is 61.44 MS/s. Doesn't Nyquist theorem state that the sampling rate should ...
-1
votes
1answer
203 views

Where to find microcontroller ADC sampling rate comparison?

I need a microcontroller with an ADC sampling rate around 100Ksps at minimally 10bits, but finding any comparisons of different microcontrollers regarding sampling rates has proven to be quite ...
4
votes
3answers
112 views

What should be the sampling frequency for a square pulse train in a DAQ system?

Since a square pulse has very high harmonics how to obtain a good resolution of pulses? For example if we have pulse train around 500 Hz could we treat it as a typical analog signal and sample it with ...
4
votes
1answer
83 views

What is the relation between multiplexing and the sampling frequency in a data acqusition system?

There is a data acquisition board recording analog signals from 10 channels with multiplexing. If one wants to sample each channel with for example 2000Hz and the number channels is 5 should the ...
3
votes
2answers
201 views

Considering Delta Sigma ADC. How to set an arbitrary sampling frequency with ADS1675

I have been reading about what delta sigma ADC (DSADC) is and if they can help me in my project and I think they will. The oversampling reduces the requirements on the analog anti-aliasing filter and ...
2
votes
1answer
147 views

phase estimation from I and Q

let say I have a discrete sine signal. I build the I and Q channel according to sampling with a frequency 4*time the signal frequency. that means multiplying the signal with [1 1 -1 -1.....]. in ...
2
votes
1answer
357 views

Interference beetween ADC samples with XBee and photoresistor

I'm using an XBee serie 2 module for sampling the values of three sensors, a photoresistor (LDR) a moisture sensor and a temperature sensor (LM35). When there is no brightness the photoresistor has ...
3
votes
1answer
524 views

8~16 PDM digital microphone + what processing? = beamformer!

I am researching on a project about sound source beam-forming. I'd like to build: 8~16 digital microphones into one 2D(circle)/3D(sphere) PCB to form an array with an equal separation of each mic 3cm ...
0
votes
1answer
212 views

what is the difference between sample method and sample and hold method

I want to know what is the difference between sample method and sample and hold method ,and why are these two methods important to study analog to digital conversion and its reconstruction back to ...
2
votes
2answers
2k views

How can I find a specific frequency after doing FFT?

I have some samples from an SDR that I run through FFT and I want to detect the presence of a specific signal, exactly 148.369MHz. The maximum sample rate of the device is 2Mhz, this is just ...
2
votes
1answer
695 views

PIC analog to digital converter to measure more than one battery voltage (with different grounds)

I'm trying to build a circuit that can scale down several lipo batteries (5 cell) up to 22V max to be safe to either 3.3V or 5V for measuring with a PIC microcontroller using the analog to digital ...
1
vote
2answers
262 views

Periodic graph in frequency domain

Why is that the frequency domain has the same shape all through out? Look at figure b
3
votes
2answers
193 views

How to measure, with timestamps, changes in the received luminance?

I'm working on a project that is in need of some testings to validate it. I need to make some readings of luminance from a light source and store this reading with a timestamp (milliseconds ...
2
votes
1answer
849 views

Wifi limitations

What are the limitations of using wifi where you have say 30+ clients/devices pushing compressed audio (flac)? bitrates: ~384 to 768 kb/s (44100 x 16 x 1 to 48000 x 16 x 1) * ( 0.5 to 1.0 ) (sampling ...
1
vote
4answers
661 views

Measuring low current at very high speed

I have a circuit with a very-low-power Jennic JN5148 module with microcontroller and 2.4 GHz radio, and some low-power sensors. I have to measure the supply current of all these components, in an ...
36
votes
6answers
4k views

Why are digital oscilloscopes still so expensive?

I'm a beginner in hobby electronics and I am wondering why digital oscilloscopes are still so expensive? In times of cheap GHz CPUs, USB 3, ADSL modems, DVB-S receivers, blu-ray players which all of ...
9
votes
3answers
3k views

Why is the Nyquist data rate lower than the Shannon data rate?

In the book Computer Networks, the author talks about the maximum data rate of a channel. He presents the Nyquist formula : C = 2H log\$_2\$ V (bits/sec) And gives an example for a telephone line : ...
2
votes
3answers
2k views

Highest ADC input signal frequency for atmega8?

I am trying to make a simple project which involves acquiring some data from the adc of atmega8 chip and then sending that data to UART. But I cannot figure out what would be the maximum limit of the ...
19
votes
5answers
5k views

How do digital oscilloscopes achieve such high sample rates?

From the perspective of data capture, how is this achieved? If I wanted to implement a home-made digital device to capture high frequency analogue signals, what are my options? So far, I've only come ...
3
votes
5answers
1k views

How to sample audio at Nyquist frequency with MSP430F5438?

I want to: Input an analog audio track Using the microcontroller ADC, convert it to a digital output Then have the microcontollers/boards timer sample the data at selected intervals Resample the ...
2
votes
1answer
238 views

What should I be using to amplify a heat flux and load cell signal?

For my senior design project, we have various sensors (Thermocouples, Heat flux sensors, load cell) plugged into our DAQ. We are using LabView and some National Instruments devices (ugh) and ...
5
votes
3answers
841 views

Increasing ADC resolution by supersampling on a successive approximation ADC

Is it possible to increase the resolution of an ADC by supersampling on a PIC24F ADC, which has 10 bits of resolution and is implemented using a successive approximation engine? Speed is not critical ...
4
votes
3answers
826 views

Equivalent time sampling on microcontrolers

I must admit, I don't know too much about analog electronics but I am keen to know if it possible to construct an equivalent time sampler (ETS) using the A/D's on a micro. I hope this question isn't ...
6
votes
2answers
1k views

What's the difference (electrically) between AC- and DC-coupled sampling circuits?

I've noticed that in analog signal acquisition hardware you see two paradigms: AC-coupled and DC-coupled. Typically AC-coupled hardware is less expensive, and basically has a 20 Hz high-pass filter ...
10
votes
8answers
12k views

Maximum sample rate of Arduino Duemilanove?

G'day all! I have an Arduino Duemilanove hanging around spare at the moment and thought I might try a few audio interfacing projects. I'm just wondering what sort of sampling frequency I can achieve ...