Signal-To-Noise Ratio Dependence On Frame Time, Time Delay And Integration (TDI), And Pulse Shaping

J. Allen Cox

doi:10.1117/12.7972941

1 June 1982 Signal-To-Noise Ratio Dependence On Frame Time, Time Delay And Integration (TDI), And Pulse Shaping

J. Allen Cox

Author Affiliations +

Optical Engineering, Vol. 21, Issue 3, 213528 (June 1982). https://doi.org/10.1117/12.7972941

Abstract

The dependence of the signal-to-noise ratio (SNR) on three important focal plane design functions frame time, time delay and integration (TDI), and pulse shaping is examined. A general focal plane model is developed that permits the SNR to be parameterized separately in terms of the three functions. The focal plane model treats both staring mosaic sensors and scanning line sensors as special cases of the model parameters and accounts for the pres-ence of multispectral detectors arranged in either a side-by-side or a sandwiched configuration. Both noise in the detectors (including photon noise) and charge coupled device (CCD) noise that arises in transferring the signal off the focal plane are considered, but it is assumed that the detectors are not limited by 1 /f noise. General parametric expressions for the SNR in terms of frame time, the number of samples per blur spot (pulse shaping), and the number of TDI steps are derived, and specific results for both a mosaic focal plane and a scanning line focal plane are presented. It is found that, regardless of the focal plane design, the SNR increases at least as the square root of the frame time and decreases at least as the square root of the number of samples per blur spot. The behavior of the SNR in terms of the number of TDI steps is more complicated and depends on the specific focal plane configuration. It can be stated generally, however, that the presence of CCD noise ultimately causes the SNR to peak and then decrease with increasing TDI. The peak SNR occurs at large TDI steps for scanning line sensors and at small TDI steps for mosaic sensors.

Citation Download Citation

J. Allen Cox "Signal-To-Noise Ratio Dependence On Frame Time, Time Delay And Integration (TDI), And Pulse Shaping," Optical Engineering 21(3), 213528 (1 June 1982). https://doi.org/10.1117/12.7972941

Published: 1 June 1982

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available