## Forums Search for: Oversampling

## Maximum useable oversampling rate10x analog signal bandwidth?

inAnalog Devices comments on their web site that for oversampling to work the sample rate cannot be over 10 times the analog signal bandwidth....

Analog Devices comments on their web site that for oversampling to work the sample rate cannot be over 10 times the analog signal bandwidth. So this defines the upper bounds on how much you can reduce the noise floor of an analog signal. So I am thinking what magical about 10x, but I suppose they are implying that if you had a 100hz bandwidth limited signal and oversampled it 1024 times at 1G...

## Oversampling algorithm for root raised cosine pulse shaping filter

inhello ! I am working on a design of a Root Raised Cosine Pulse Shaping Filter and my design of filter taps are on the basis of sampling...

hello ! I am working on a design of a Root Raised Cosine Pulse Shaping Filter and my design of filter taps are on the basis of sampling frequency which is of 4 times the BB frequency. Now to use this filter in the Tx section, I need to oversample my input data by 4 times. I would like to have a suggestion from you regarding the type of Oversampling Algoirthm that I can use for this purpose. ...

## how to understand sigma-delta adc in time domain?

inI'm trying to think of a way to understand sigma-delta ADCs in time domain. Up to my understanding, two key technology of sigma-delta ADCs...

I'm trying to think of a way to understand sigma-delta ADCs in time domain. Up to my understanding, two key technology of sigma-delta ADCs are oversampling and noise shaping. In frequency domain, oversampling evenly spreads the square(delta)/12 quantization noise between 0 and samping frequency fs. Then with the help of decimation filter, we can remove the noise out of baseband fB. So, the rem...

## Oversampling

inHi All, Can anyone provide matlab code fragments to explain to me how to use the kronecker delta to oversample a signal, s, by a factor of k...

Hi All, Can anyone provide matlab code fragments to explain to me how to use the kronecker delta to oversample a signal, s, by a factor of k ? I'd really appreciate any help anyone can give on this, Many thanks, R.

## Sigma Delta Modulator A/D

inI have read a bit about oversampling. Understand most of the theory but get stuck at the easy bit. If we sample with one a one bit ADC - how...

I have read a bit about oversampling. Understand most of the theory but get stuck at the easy bit. If we sample with one a one bit ADC - how do we get 16 bits back from this single bit to do the processing? Naebad

## implementing on dsp

inI have to implement several QPSK narrowband carriers 24 ksym/sec,32Khz BW I have several basic questions since I've haven't worked with...

I have to implement several QPSK narrowband carriers 24 ksym/sec,32Khz BW I have several basic questions since I've haven't worked with DSPs before and am in the process of data collection before I pick a processor. 1. I want to do several of these channels in 1 dsp,since I will only be doing scrambling,encoding, and pulse shaping(oversampling by 5) then output I and Q at baseband each going...

## manchester encoding decoder

inHi, I have to implement a receiver/decoder for a typical manchester encoded signal. I have to use a mircocontroller for this. someone tipped me...

Hi, I have to implement a receiver/decoder for a typical manchester encoded signal. I have to use a mircocontroller for this. someone tipped me on using what he called "oversampling and counter algorithm". but i can't find any useful reference. any help please. cheers PS. I have no background on communication

## My first Digital Filter: Can I ask your help?

inHello this is the first time that I approach to DSP so I'm really newbie. I have to write a program that realize a Low Pass Filter at 50...

Hello this is the first time that I approach to DSP so I'm really newbie. I have to write a program that realize a Low Pass Filter at 50 Hz. My processor (ATTINY) have 10bit ADC so for first time I have used Oversampling and Decimation technique for add 3 "Virtual Bit" First Question: Since my Oversampled Frequency is: 4^3 * F-nyquist = 64 * 100 = 6.4KHz ...

## Oversampling and the FFT

inHello, I was recently working with a DSP engineer who was making an argument to me that if I didn't oversample (above Nyquist) that I would be...

Hello, I was recently working with a DSP engineer who was making an argument to me that if I didn't oversample (above Nyquist) that I would be "losing information," and I still fail to understand exactly what information I would be losing. The context of our particular application, is that we are dwelling on a signal for a fixed period of time (a design constraint), but we can sample at whatever ...

## ADSL Demodulation

inHello, In every book and article aobut ADSL processing the A/D and D/A sample rates are given as 2.208 MHz. For a transmitter implementation...

Hello, In every book and article aobut ADSL processing the A/D and D/A sample rates are given as 2.208 MHz. For a transmitter implementation at this sample rate you would get the conjugate symmetric image spewing out of your D/A since one may use up to bin 255 and there is absolutely no oversampling, and no analog filter in the world can cut-off that fast. Likewise for the receiver, any si...

## Oversampling in OFDM

inHi, I have a question related with the OFDM transmitter. What is the commonly method to increase the sampling rate ? - Increasing the IFFT...

Hi, I have a question related with the OFDM transmitter. What is the commonly method to increase the sampling rate ? - Increasing the IFFT size and insert zero in the inpput ? or - Insert zero in the IFFT output and followed by interpolation filter ? What is the trade-off ? anyone can help ? Thanks. Buzz

## Non-ovesampling DACs vs. Oversampling DACs for audio - your feedback requested

inI came across a link today to an article about the merits of a non-OS DAC over an OS DAC. Of course, I'm referring to the filter part of the...

I came across a link today to an article about the merits of a non-OS DAC over an OS DAC. Of course, I'm referring to the filter part of the DAC. Anyway, this article doesn't make much sense to me: http://www.sakurasystems.com/articles/Kusunoki.html What is your take on this? Is the author correct when he says that 16-bit accuracy is not possible if you oversample? I don't believe th...

## FFT Size calculation.

inHi, I have the following problem that I am trying to address. Lets say we take 64 numbers and apply FFT of size 64. Then we concatenate 100...

Hi, I have the following problem that I am trying to address. Lets say we take 64 numbers and apply FFT of size 64. Then we concatenate 100 of these 64 numbers, and perform D/A conversion. This signal is digitized at a rate other than the original sampling rate, say we have oversampling of 3/2. Then per FFT we have 96 samples. And further assume that I know I have 96 samples per FFT (but I...

## dsPic adc for audio signals

inHi. With a dsPic (ie dsPic30F4013) I need to process two voice band channels (for telephony, fs=8kHz). Can there be problems to use the...

Hi. With a dsPic (ie dsPic30F4013) I need to process two voice band channels (for telephony, fs=8kHz). Can there be problems to use the embedded adc, oversampling 8 times and then filtering? Do you think this may waste more than one half of dsp bandwidth? Why is not usual to use the embedded adc for audio signals? Thank you. pp

## Choice of Oversampling Ratio in Comm Simulations

inHi Folks, When we simulate a communication system, say, QPSK with simple AWGN, I've noticed that a high sample rate (N*Fsym Fsymthe symbol...

Hi Folks, When we simulate a communication system, say, QPSK with simple AWGN, I've noticed that a high sample rate (N*Fsym Fsymthe symbol rate) is used. Typically it seems N=8. Why is this done? -- % Randy Yates % "She's sweet on Wagner-I think she'd die for Beethoven. %% Fuquay-Varina, NC % She love the way Puccini lays down a tune, and %%% 919-577-9882 ...

## changing sampling rate from 10Ksps to 10.8ksps

inHi All, I need your help in order to find a solution at the following problem: I need to change the sampling rate of a signal from the...

Hi All, I need your help in order to find a solution at the following problem: I need to change the sampling rate of a signal from the original 10ksample per sconds to 10.2 ksps. I should to do this without oversampling and decimation...which other possibilities I have? Ther is a rule that I should apply in all the case where the starting frequency and the final frequency are very clos...

## Question related to Sigma-Delta Datasheets

inHi All, I am going to be selecting a specific sigma-delta converter for an application and am getting a bit confused on the terminology. I...

Hi All, I am going to be selecting a specific sigma-delta converter for an application and am getting a bit confused on the terminology. I have read up on the theory and understand it. Looking at this datasheet: http://focus.ti.com/lit/ds/symlink/ads1251.pdf On the first page, it says 20kHz data rate. Further down, on page 8, it talks about the oversampling and says that the output r...

## Question about damping in PLL

inHi, I am learning PLL from a web download PLLTutorialISSCC2004.pdf after I read two books on PLL. I do not understand the following...

Hi, I am learning PLL from a web download PLLTutorialISSCC2004.pdf after I read two books on PLL. I do not understand the following statements from the web pdf: ........................... Less ringing and overshoot as Zeta = 1 Severe overdamping --> ringing and overshoot Ringing at high damping due to low oversampling (large R) Gardner limit. ............. Low damping ---> l

## Oversampling w/ Drop interpolation

inI had a question posed to me today that got me thinking. Here was the question: "If the signal is oversampled by 10 x fs and then only every...

I had a question posed to me today that got me thinking. Here was the question: "If the signal is oversampled by 10 x fs and then only every 10'th data point is used for the final data set (without any filtering of the rest of the data points) will there be any difference in the noise from data that is sampled at only fs? The result is the same number of points." My answer was yes, ...

## Strange fm component in the ECG

inDear all, We are acquiring the ECG with a high resolution system, sampling frequency 2400Hz. The system is an oversampling sigma delta, 24...

Dear all, We are acquiring the ECG with a high resolution system, sampling frequency 2400Hz. The system is an oversampling sigma delta, 24 bits. In some ECG´s (from normal subjects and patients) we get, added to the ECG, a frequency modulated version of the ECG itself, e.g. a sinus wave with constant amplitude and whose instant frequency is proportional to the ECG signal value in that partic...