i like this post (click again to cancel)
1
i dont like this post (click again to cancel) remove favorite mark from this question (click again to restore mark)

Is acquisition bandwidth and receiver bandwidth the same?? am confused with the terminology....please clarify....thanks

asked Feb 07 '11 at 10:41

cyclone's gravatar image

cyclone
21


3 Answers:
i like this answer (click again to cancel)
1
i dont like this answer (click again to cancel)

Not sure I understand the question but maybe the distinction could be along these lines:

Acquisition bandwidth = sweepwidth i.e. 1/dw were dw = acquisition dwell time for a given experiment (assuming 'normal' as opposed to 'digital' signal acquisition. Think Nyquist.

Receiver bandwidth = the maximum possible sweepwidth corresponding to the shortest dw that you can set on your spectrometer.

link

answered Feb 10 '11 at 03:17

Paul%20Driscoll's gravatar image

Paul Driscoll
81

i like this answer (click again to cancel)
1
i dont like this answer (click again to cancel)

They may be similar in scope, but technically they are different terms. Simply put, there is a digitiser and a Fourier transform in between them.

NMR receivers are relatively narrow band devices. They see only the Intermediate Frequency (IF) after the NMR signal is heterodyned down in frequency by a mixer. That's how we observe more than one nucleus with a single receiver. Receiver bandwidth needs to be only wide enough to encompass the frequencies in the FID.

Acquisition BW is 1/PW, is it not? Compared to the hundreds of MHz in the original signals, the observed spectral bandwidth of a few KHz is also pretty narrow (ppm). This might deserve correction, but wouldn't the maximum spectral bandwidth available be determined by the speed of the digitizer divided by 2.2?

link

answered Feb 11 '11 at 10:11

Jerry%20Hirschinger's gravatar image

Jerry Hirschinger
199

i like this answer (click again to cancel)
1
i dont like this answer (click again to cancel)

The bandwith should be interpreted in conjunction with the term carrier frequency. The spectrometer frequency is the carrier frequency and the NMR information is contained in about a few Kilohertz range (audio frequency) around the Carrier frequency. Intermediate Frequency is also a carrier RF frequency obtained from the original spectrometer frequency for electronic considerations. The NMR information is obtained by the Phase Sensitive detection (demodulating) of the carrier frequency with appropriate reference frequency. Till the end stage of the detection this bandwidth consideration is determined by the NMR signal spread from the carrier frequency which is termed the receive bandwidth. The digitization is by the A/D converter at the final stage of receiving the analogue signal before storing it in the computer memory.

Aravamudhan

link

answered Feb 14 '11 at 07:36

SankarampadiAravamudhan's gravatar image

SankarampadiAravamudhan
91

Your answer
Please start posting your answer anonymously - your answer will be saved within the current session and published after you log in or create a new account. Please try to give a good answer, for discussions, please use comments and please do remember to vote (login to vote)
toggle preview

Tags:

×2

Asked: Feb 07 '11 at 10:41

Seen: 7,009 times

Last updated: Feb 14 '11 at 07:36

Related questions

powered by CNPROG