Calibration of PPTA Data R. N. Manchester Australia Telescope National Facility, CSIRO Sydney Australia Summary Effect of calibration on timing Non-linearities in system response Time stability of calibration parameters

PSR J Timing Residuals 20cm Multibeam Receiver PDFB1, June 05 - Nov 07 Mostly 1-h observations  Uncalibrated Rms Residual: 1.23  s  Calibrated instrumental gain and phase Rms Residual: 0.74  s  Jump around H-OH data Rms Residual: 0.65  s  PCM calibration - no jump Rms Residual: 0.72  s  PCM Cal with jump Rms Residual: 0.59  s

Raw Calibration Amplitudes PDFB1, June 05 - Nov 07 Cal amplitudes in counts (obtained using pdv -c) Initially operating with input levels too high Levels further reduced after linearity tests Apart from non-linear effects, absolute levels don’t matter provided cal and psr observations done with same settings

Effect of Non-Linearities PDFB1, MB Receiver Saturation effects Vela Pulsar, 20cm band WBC, H-OH Receiver 2-bit digitisation effects, feed resonances, correlator artifacts Plotted profiles truncated at 5% of peak

System Linearity PDFB2, MB receiver Pulsed calibration used as test signal Adjust input signal levels using down-converter attenuators Measure digitiser rms, cal amplitudes and apparent fractional linear polarisation of calibration System reasonably linear over input rms range of , i.e. 20 db range of input power Operating point of rms = 10 chosen Similar level tests done for PDFB1

Linearity with Current Settings for Input Levels Vela Pulsar, MB Receiver PDFB1 PDFB2 5% truncation of profiles

Pulsed Cal Mean Flux Densities Centre beam Multibeam receiver, 1369 MHz Mean values from pacv

PDFB2: 11 Sept 2007 PDFB1: 16 June 2007 PDFB2: 01 Oct 2007 WBC: 22 Dec 2005 Calibration Flux Density Spectra Multibeam Receiver - based on observations of Hydra A

09 May June Aug 2007 Feed Cross-Coupling Parameters PDFB1, Multibeam Receiver 1369 MHz Polarisation ellipse orientation and ellipticity