LFR Calibration Activities (sub-system level) LFR team at LPP Thomas Chust Lead Co-I (CNRS) science, calibration, tests Paul Leroy Technical Manager (CNRS) flight software development + SGSE Alexis Jeandet Lead Engineer (CNRS) hardware development, GSE + SGSE Jean-Christophe Pellion Engineer (CDD) VHDL developement Vincent Leray (20%) product assurance hardware William Recart (20%) product assurance software Bruno Katra Engineer (CNRS) software developement, calibration, tests, GS Véronique Bouzid flight software specification / validation Fouad Sahraoui Co-I (CNRS) science Alessandro Retino Olivier Le Contel science + SCM calibration

Outline Presentation of the LFR products On-ground LFR sub-system calibration Current activities @ LPP

RPW Instrument Overview Will allow the characterization of the electric and magnetic fields associated to the dynamics of the near-Sun heliosphere from near DC up to 20 MHz Main Electronic Box (MEB) Electric Antennas (ANT) 3xV V LF Bias Unit V Sp W 1 1HF Floating volt age dr iver V 5xV BIAS 2HF V 3HF 3xV HF TNR-HFR V Auto & cr oss-spectr a Sp W 1LF 1xB (4kHz-20MHz) V HF 2LF V V V 2 3LF 3 3xV Nom. SpW HF TDS to/from S/C 1xB HF Wavefor m @ 500kS/s Sp W 3xV BIAS + LFR Redundancy RPW-DPU Search Coil Magnetometer 3xB LF (SCM) Red. SpW to/from S/C B 2LF 5xV LFR BIAS Waveform up to 25kS/s 3xV Sp W B HF 3LF + Auto & cross- spectr a 3xB LF + k- vector (~DC-10kHz) B 1LF 3.3V 2. 5V 5V +/ -1 2V B 1HF 28 V LVPS-PDU from S/C Low Frequency Receiver

LFR 11 analogue inputs

LFR Decimation and Processing Strategy 8 ADCs @ 98 304 Hz decimation down to ß 24 576 Hz ( f0 ) (14 bits ideally) :32 :3 (16 bits) (15 bits) (16 bits) (16 bits) 24 576 Hz 4 096 Hz 16 Hz 256 Hz shaping :3 :2 :64 :4 [20 bits ?] [18 bits ?] ( f1 ) ( f3 ) ( f2 ) :4 ( f0 ) 2  E 3  B 1  V 2  E 3  B 2  E 3  B 1  V 2  E 3  B 1  V 2  E (3  B) 2  E 3  B 1  V 2  E 3  B FFT FFT FFT (15 bits) Spectral matrices (ASM) Waveforms (WF) Spectral matrices (ASM) Waveforms (WF) Waveforms (WF) Spectral matrices (ASM) Waveforms (WF) Basic parameters (BP) Basic parameters (BP) Basic parameters (BP)

BIAS 5 analog inputs and the R-parameters DC V (G=1/15) DC dV ~ E (G=1) AC dV ~ E (G=5 or 100, cutoff~8Hz) R2

LFR Normal Mode (1) Basic Parameters sampling frequency ... BP: 1080 bps WF: 2734 bps ASM: 32 bps TM: 3846 bps Basic Parameters sampling frequency BP1 & BP2 BP1 & BP2 BP1 BP1 BP1 ASM BP1 4 SMs 64 SMs 384 SMs 4 SMs 64 SMs 384 SMs 4 SMs 64 SMs 384 SMs 4 SMs 64 SMs 384 SMs 4 SMs 64 SMs 384 SMs 4 SMs 64 SMs 384 SMs 4 SMs 64 SMs 384 SMs f0 = 24576 Hz ... TBP1_0= 4 s ... f1 = 4096 Hz ... TBP1_1= 4 s ... f2 = 256 Hz ... TBP1_2= 4 s ... ... 4 s continuous WF ... f3 = 16 Hz 20 s time

WaveForms & Averaged Spectral Matrices LFR Normal Mode (2) WaveForms & Averaged Spectral Matrices TASM= 3600 s sampling frequency TWF= 300 s WF BP1 ASM BP1 WF 384 SMs 384 SMs 384 SMs f0 = 24576 Hz 1/12 s ... ... ... 64 SMs 64 SMs 64 SMs f1 = 4096 Hz 1/2 s ... ... ... 4 SMs 4 SMs 4 SMs f2 = 256 Hz 8 s ... ... ... 2048 pts ... 4 s ... continuous WF ... f3 = 16 Hz time

LFR Selected Burst Mode 1 BP: 12672 bps WF: 393216 bps ASM: 0 bps TM: 405888 bps sampling frequency BP1 & BP2 BP1 & BP2 BP1 BP1 BP1 BP1 BP1 24 SMs 24 SMs 24 SMs 24 SMs 24 SMs 24 SMs 24 SMs f0 = 24576 Hz ... TBP1_0= 0,25 s ... 0,25 s f1 = 4096 Hz ... continuous WF ... 1 s time

LFR Selected Burst Mode 2 BP: 5760 bps WF: 24576 bps ASM: 0 bps TM: 30336 bps sampling frequency BP1 & BP2 BP1 & BP2 BP1 BP1 BP1 BP1 BP1 96 SMs 96 SMs 96 SMs 96 SMs 96 SMs 96 SMs 96 SMs f0 = 24576 Hz ... TBP1_0= 1 s ... 16 SMs 16 SMs 16 SMs 16 SMs 16 SMs 16 SMs 16 SMs f1 = 4096 Hz ... TBP1_1= 1 s ... f2 = 256 Hz ... 1 s continuous WF ... 5 s time

On-ground LFR sub-system calibration LFR will be calibrated on-ground in a standalone configuration across the entire frequency and amplitude range to properly characterize the : analogue to digital conversions filter responses gain factors reference voltage levels uncertainties in the on-board computation of spectral products In particular, the aim is to determine for each frequency channel (f0, f1, f2, and f3) : the frequency response (amplitude & phase) associated to the analog and digital filters the group delay between the input signals and the output data the relative gain and phase shift for all pairs of input channels; the maximum measurable level associated with the saturation of electronics; the minimum measurable level associated with the electronics noise and the finite number of bits the large (near-saturation) narrow-band signal dynamic range ...

On-ground LFR sub-system measurements Measurement of the noise floors of the waveforms Measurement of the noise floors of the spectral matrices Measurement of the transfer functions to be applied to the waveforms Measurement of the transfer functions to be applied to the spectral matrices Measurement of the dynamic ranges of the waveforms Measurement of the dynamic ranges of the spectral matrices Measurement of the white noise responses in terms of waveforms Measurement of the white noise responses in terms of spectral matrices Measurement of the uncertainties in the computation of the wave parameters

LFR Engineering Model (EM1) FPGA ADCs (RTAX4000 emulator) November 2013

Noise floors of the waveforms (1) Long continuous waveforms of output signals will be recorded (in count unit) with LFR inputs let free. Set of waveform data representing all possible working configurations of the receiver for continuous measurements. The waveform data are then analyzed in order to retrieve the main characteristics of the noise observed for each of these output signals. One will compute their offset, their standard deviation and their frequency power spectrum; one will also check their stability in time. Same for a large number of successive waveform snapshots ...

Noise floors of the spectral matrices Successive and a large number of spectral matrices will be recorded (in count unit) with LFR inputs let free. Set of spectral data representing all possible working configurations of the receiver for auto- & cross-correlation measurements. It will constitute reference noise measurements for the LFR on-board spectral computation. The stability in time will also be checked. Results obtained from the original spectral matrices (ASM_F0, ASM_F1, and ASM_F2, respectively), will be compared with those obtained from the normalized ones (BP2_F0, BP2_F1, and BP2_F2, respectively).

Transfer functions for waveforms (1) Constant input signals One will start by measuring the scale factors that allow to convert count unit to Volt unit for constant input signals (zero frequency). In a first time, one will inject a +1.0 V amplitude signal in all possible input channels and will record the corresponding waveform data with all possible working configuration of the receiver. The configurations to be used are thus the same as for the noise floor measurements of the waveforms. In a second time, one will redo the same but with a -1.0 V amplitude signal. The comparison between the two cases allows for the determination of the offsets and thus getting rid of them. (or one will inject a very low frequency rectangular signal ...)

Transfer functions for waveforms (2) Sinusoidal input signals One will inject 2.0 Vpp sinusoidal signals and sweep over the full frequency range. Again all possible input channels will be considered and the corresponding waveform data will be recorded with all possible working configuration of the receiver. Thus, same configurations as for the noise floor measurements of the waveforms. For continuous waveform measurements the frequency resolution is not limited and can be as good as 0.01Hz : CWF_F1 : frequency range of analysis = [0.01Hz-2048Hz] CWF_F2 : frequency range of analysis = [0.01Hz-128Hz] CWF_F3 : frequency range of analysis = [0.01Hz-16Hz] For waveform snapshot measurements the frequency resolution is limited by the number of samples (2048) recorded by snapshot : SWF_F0 : frequency range of analysis = [12Hz-12288Hz] SWF_F1 : frequency range of analysis = [2Hz-2048Hz] SWF_F2 : frequency range of analysis = [1/8Hz-128Hz]

Transfer functions for waveforms (3) Sinusoidal input signals (continued) Frequency responses in amplitude For each considered frequency, the responses in amplitude will be determined by computing the standard deviations of the output signals. The offsets will be determined by computing the averages, which should be independent from the frequencies. Time stability will also be investigated. (or by computing the FFT ...) Frequency responses in phase Necessitate a synchronization between the input and output signals. This will be done by triggering the start of the input signals by a pulse synchronized with the receiver. This procedure is on going. Meanwhile (or as second procedure) we will consider the addition of two sinusoidal signals where one of them will be considered as the reference signal (at a given frequency fref ). The measurement of the phase shift between the two output sinusoidal signals will allow for the determination of the response in phase relative to the reference signal

Experimental facility for LFR calibration On going ... 4 x trigger Mini-LFR = up to 8 analog signals EM

Transfer functions for waveforms (4) Sinusoidal input signals (continued) Relative gains and phase shifts Ideally it would be interesting to perform the measurements for all pairs of input channels. For practical reason we will consider the most important ones, which are sufficient for reconstructing all possible relative gains and phase shifts. This set of input pairs will be associated to all possible working configuration of the receiver One will inject 2.0 Vpp sinusoidal signals in these pairs and sweep over the same frequency ranges as for the determination of the frequency responses. For each considered frequency, the corresponding pair of output waveform data will be recorded. Their relative gain and phase shift will be determined by computing their cross-correlation. Time stability will again be investigated.

Transfer functions for spectral matrices One will inject simultaneously five 2.0 Vpp sinusoidal signals, with same phase, on the LFR inputs. And sweep over the full frequency range with multiple of the on-board frequency resolution (f0/256, f1/256 or f2/256). One will use all possible working configurations of the receiver for auto- & cross-correlation measurements. These are the same as defined for the determination of the noise floors of the spectral matrices. Successive and a large number of the corresponding spectral matrices will be recorded (in count unit). They will constitute reference sinusoidal signal measurements for the LFR on-board spectral computation. The stability in time will also be checked. Results obtained from the original spectral matrices (ASM_F0, ASM_F1, and ASM_F2, respectively), will be compared with those obtained from the normalized ones (BP2_F0, BP2_F1, and BP2_F2, respectively). (indeed one more signal is needed if the dependency with VHF_1 has to be taken into account ...)

Dynamic ranges of the waveforms (1) Measurements will be done with constant and triangular signals. (BW=1, R0=1, R1=1, SP0=0, SP1=0) 9 Vpp F = 1.523810 Hz +29291 counts B1 -29208 counts B2

Dynamic ranges of the spectral matrices Measurements will be done with two superposed sinusoidal signals. One with large amplitude, the second one with small amplitude.

Dynamic ranges of the spectral matrices The smallest sinusoidal signal detectable with the ASM_F1 is presently (to my best knowledge) : ~ 1 mVpp => ~ 9 counts pic to pic Tbw ...

White noise responses Another way to measure the frequency response in amplitude ... Another way to evaluate saturation levels ... Again both in terms of waveforms and spectral matrices ...

Uncertainties on the wave parameters Concern the uncertainties in the on-board computation of the wave parameters (BP1) derived from the ASM Tbw ...

Expected calibration parameters For each frequency channel of data products (f0, f1, f2 or f3), the on-ground LFR calibration will determine : the transfer functions to be applied to the waveforms (WF) and the spectral matrices (ASM and BP2) the large (near-saturation) narrow-band signal dynamic ranges of the waveforms (WF) and the spectral matrices (ASM and BP2) the noise floors of the waveforms (WF) and the spectral matrices (ASM and BP2) the white noise broadband responses in terms of waveforms (WF) and spectral matrices (ASM and BP2) the uncertainties in the on-board computation of the wave parameters (BP1) derived from the ASM

Additional slides

LFR operational modes data produced and sent to DPU: data subsequently transmitted to S/C:   NM all (SW In-Situ) BM LFR ~10 min all NM (Shock) SBM1 ~15 min NM all (Type III) SBM2 90 - 120 min

LFR block diagram

LFR processus chain

LFR processus chain

BIAS configuration