Radiometric CMB measurements need to be highly stable and this stability is best obtained with differential receivers. The residual 1/f noise in the differential output is strongly dependent on the radiometer input offset which can be cancelled using various balancing strategies. In this paper we discuss a software method implemented in the PLANCK-LFI pseudo-correlation receivers which uses a tunable gain modulation factor, r, in the sky-load difference. Numerical simulations and experimental data show how proper tuning of the parameter r ensures a very stable differential output with knee frequencies of the order of few mHz. Various approaches to calculate r using the radiometer total power data are discussed with some examples relevant to PLANCK-LFI. Although the paper focuses on pseudo-correlation receivers and the examples are relative to PLANCK-LFI, the proposed method and its analysis is general and can be applied to a large class of differential radiometric receivers.
Offset balancing in pseudo-correlation radiometers for CMB measurements / A. Mennella, M. Bersanelli, M. Seiffert, D. Kettle, N. Roddis, A. Wilkinson, P. Meinhold. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 410:3(2003), pp. 1089-1100.
|Titolo:||Offset balancing in pseudo-correlation radiometers for CMB measurements|
MENNELLA, ANIELLO (Primo)
BERSANELLI, MARCO RINALDO FEDELE (Secondo)
|Parole Chiave:||Cosmology: cosmic microwave background, observations; Instrumentation: detectors; Methods: analytical|
|Settore Scientifico Disciplinare:||Settore FIS/05 - Astronomia e Astrofisica|
Settore FIS/01 - Fisica Sperimentale
|Data di pubblicazione:||2003|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1051/0004-6361:20031266|
|Appare nelle tipologie:||01 - Articolo su periodico|