Bandwidth Per Pixel
Convert full-span ADC receiver bandwidth to frequency-encoding bandwidth per reconstructed readout sample; vendor half-bandwidth conventions must be converted first.
Description
Receiver bandwidth per readout pixel divides a total spectral span by the readout sample count.
Receiver bandwidth per readout pixel divides a total spectral span by the readout sample count. It is a scalar acquisition convention rather than an image measurement.
The tool returns hzPerPixel (hz per pixel). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Bandwidth Per Pixel
Use Bandwidth Per Pixel when you already have totalReceiverBandwidthHz, readoutSamples and want hzPerPixel. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Bandwidth Per Pixel and understand its results
- Enter totalReceiverBandwidthHz, readoutSamples using the field table below. Match the units, ordering and data boundaries described in the calculation.
- Run the tool after checking the stated bounds and matching paired observations or categories. A malformed request gives a tool error rather than a usable measurement.
- Read hzPerPixel. Use the calculation and interpretation below to distinguish amounts, ratios, signs and decision flags where applicable.
- Review the supplied parameters and assumptions before using the result in a report or comparing it with another observation.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| totalReceiverBandwidthHz | Total receiver bandwidth hz | number | Required |
| readoutSamples | Readout samples | integer | Required |
Use positive total bandwidth and a positive integer sample count.
Hz/pixel = totalReceiverBandwidthHz/readoutSamples The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"totalReceiverBandwidthHz": 51200,
"readoutSamples": 256
},
"output": {
"hzPerPixel": 200
}
}Limitations and assumptions
The total-bandwidth convention must match the scanner. Oversampling, reconstruction and phase-direction bandwidth are not inferred.
Numerical inputs must be finite. The tool checks its declared input shape and calculation constraints; those checks do not verify the quality, calibration or representativeness of the supplied observations.
Alternative or Complementary methods
Chemical Shift Artifact Pixels: Estimate signed frequency-encoding chemical-shift displacement using supplied shift, reference frequency and pixel bandwidth; direction depends on readout polarity. Readout Time: Distinguish N full ADC dwells from the (N−1)-dwell first-to-last timestamp span; gradient ramps are not included.
Methodological background: RAD229: MRI signal and sequence lecture notes.1
References
-
RAD229: MRI signal and sequence lecture notes — Brian Hargreaves and colleagues, Stanford University
Similar or alternative tools
- Chemical Shift Artifact Pixels
Estimate signed frequency-encoding chemical-shift displacement using supplied shift, reference frequency and pixel bandwidth; direction depends on readout polarity.
- Readout Time
Distinguish N full ADC dwells from the (N−1)-dwell first-to-last timestamp span; gradient ramps are not included.