Signal Processing. For each recorded sample the autopower spectrum shall be determined, using a Xxxxxxx window and at least 66.6% overlap averages. The reported speed is the average of the speed during the time sample. In case of test method (A) the [four] determined spectra per test speed shall be energetically averaged. The resulting average spectrum per test speed shall be used for the further calculation. In all other cases the derived frequency spectrum shall directly be used for the further calculation. The reported speed is the average of the [four] measurements.
Signal Processing. For each recorded sample the average auto power spectrum shall be determined, using a Xxxxxxx window and at least 66.6% overlap averages. The frequency resolution shall be chosen sufficiently narrow to allow a separation of the frequency shift per target condition. The reported speed per sample segment is the average vehicle speed over the time of the sample segment. In case of test method (A) the frequency that is intended to be changed with the speed shall be determined per sample segment. The reported frequency per target condition fi,speed shall be the mathematical average of the frequencies determined per measurement sample and rounded to the nearest integer. The reported speed per target condition shall be the mathematical average of the [four] sample segments, rounded to the first decimal. Target speed Test run per target condition Reported speed (average per sample segment) Determined frequency of interest (peak in the sample segment) Reported Speed per target condition (average of the reported speeds) Reported frequency of interest per target condition (fi,speed) km/h km/h Hz km/h Hz 10 1 15 1 Table [2]: Analysis of the shifted frequency per target condition per side For all other test methods the derived frequency spectrum shall directly be used for the further calculation.
Signal Processing. For each recorded sample the autopower spectrum shall be determined, using a Xxxxxxx window and at least 66.6% overlap averages. The reported speed is the average of the speed during the time sample. In case of test method (A) the frequencyies intended to be shifted and the corresponding level determined in each test run shall be mathematically averaged. [four] determined spectra per test speed shall be energetically averaged The reported speed is the average of the four measurements. The resulting averages spectrum per test speed shall be used for the further calculation. In the case of test methods (B) to (E) all other cases the frequency intended to be shifted and the corresponding level shall be the derived frequency spectrum shall directly be used for the further calculation. The reported speed is the average of the [four] measurements.
Signal Processing. For each recorded sample the average auto power spectrum shall be determined, using a Hanning windxx xxx at least 66.6 per cent overlap averages. The frequency resolution shall be chosen to be sufficiently narrow as to allow a separation of the frequency shift per target condition. The reported speed per sample segment is the average vehicle speed over the time of the sample segment rounded to the first decimal place. In case of test method (A) the frequency that is intended to be changed with the speed shall be determined per sample segment. The reported frequency per target condition fspeed shall be the mathematical average of the frequencies determined per measurement sample and rounded to the nearest integer. The reported speed per target condition shall be the mathematical average of the four sample segments.
Signal Processing. Echoes received by the piezoelectric element are too weak to be displayed directly after reception and so need to be amplified. The first step is to amplify all returning echoes by the same factor, this being represented by the overall gain on an ultrasound machine. Because of tissue attenuation echoes returning from deeper tissues are weaker than those from more superficial interfaces. In order to achieve the aim of B – mode imaging, i.e. to relate brightness on the screen to the strength of returning echoes, echoes that take longer to arrive are amplified more to counteract the effect of tissue attenuation. Returning echoes are then compressed and digitised so that the analogue signal received by the transducer is converted to a binary number representing the signal amplitude. In order to correctly display a B-mode image, apart from echo amplitude and the position of the scan line relative to other returning echoes, it is necessary to know the range of the echo to be displayed.
