Document ID: chunk:federal_register_of_legislation:F2021C00477:body:0:p79
Version: federal_register_of_legislation:F2021C00477
Segment Type: other
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Character Range: 206439–209229

increments of 1 N pedal force. The result is the mean deceleration versus brake pedal force curve, which will be referred to as the "maF curve" in this appendix.
1.7. The maximum value for the vehicle deceleration is determined from the "maF curve" and is named as "amax".
1.8. All values of the "maF curve" that are above 90 per cent of this deceleration value "amax" are averaged. This value of "a" is the deceleration "aABS" referred to in this annex.
1.9. The minimum force on the pedal (FABS) sufficient to achieve the deceleration aABS is defined as the value of F corresponding to a= aABS on the maF curve.

Annex 9

Appendix 5

Data processing for the BAS
(see paragraph 2.2.3. of section B of this annex)
1. Analogue data processing
 The bandwidth of the entire, combined transducer/recording system shall be no less than 30 Hz.
 In order to execute the necessary filtering of signals, low-pass filters with order 4 or higher shall be employed. The width of the pass band (from 0 Hz to frequency fo at ‑3 dB) shall not be less than 30 Hz. Amplitude errors shall be less than ±0.5 per cent in the relevant frequency range of 0 Hz to 30 Hz. All analogue signals shall be processed with filters having sufficiently similar phase characteristics to ensure that time delay differences due to filtering lie within the required accuracy for time measurement.
 Note: During analogue filtering of signals with different frequency contents, phase shifts can occur. Therefore, a data processing method, as described in paragraph 2. of this appendix, is preferable.
2. Digital data processing
2.1. General consideration
 Preparation of analogue signals includes consideration of filter amplitude attenuation and sampling rate to avoid aliasing errors, and filter phase lags and time delays. Sampling and digitising considerations include pre-sampling amplification of signals to minimize digitising errors; number of bits per sample; number of samples per cycle; sample and hold amplifiers; and time-wise spacing of samples. Considerations for additional phaseless digital filtering include selection of pass bands and stop bands and the attenuation and allowable ripple in each; and correction of filter phase lags. Each of these factors shall be considered in order to achieve a relative overall data acquisition accuracy of ±0.5 per cent.
2.2. Aliasing errors
 In order to avoid uncorrectable aliasing errors, the analogue signals shall be appropriately filtered before sampling and digitising. The order of the filters used and their pass band shall be chosen according to both the required flatness in the relevant frequency range and the sampling rate.
 The minimum filter characteristics and sampling rate shall be such that:
(a) Within the relevant frequency range of 0 Hz to fmax