null position

null position

null positionclick for a larger image
The position of an ADF (automatic direction finder) loop antenna when the signal being received is canceled in the two sides of the loop, and the signal strength is the weakest. At this position, the transmitting station lies in line with the direction of the loop—either ahead or to the rear. A sense aerial is used to remove this ambiguity.
References in periodicals archive ?
The HIT0 was performed with passive brisk movements of the patient s head from the 0[degrees] null position to 20[degrees] sideways, and the HIT1 was performed toward the center while the null position was a 20[degrees] head rotation to the right and to the left.
At this time, there is no stub at the other null position of the electric field located on the right side.
The aim of this study was to show whether using the null position on the EVD provides adequate inter-hour trending of a patient's ICP.
It can be seen from Figure 9(b) that the null position of the best result obtained by QPSO in [14] is not accurate.
Emphasizing that it is time for Arab youth to speak up on this issue, Fakhri explained "decision-makers in the region have always had a null position and this is not acceptable for us, especially as youth whose futures are jeopardized by the problems that this climate catastrophe causes."
The number of nulls doubles and the 20dB power point drops when the operating frequency is doubled and the pattern of the null position is aperiodic.
Initially the spool is at null position. The stepper motor is rotated to some angle, there by moving the spool of servo valve.
This makes an LVDT perform well as a null position sensor in closed-loop control systems and high-performance servo balance instruments.
As the probe slides away from a null position, the voltage can be seen increasing to a peak before decreasing to zero again at the next null.
And, because an LVDT typically has no end position stops, the null position, located in the middle of the range of motion of the LVDT's core, is the "stake in the ground" for determining core position and is always specified on an LVDT data sheet.
The resulting patterns are shown in Figure 6 which clearly shows that the required null position centered at [[theta].sub.jammer] = 20[degrees] has been achieved and a gap of 20 dB in the side lobe between both sides of the main beam has been obtained.
After sensor failure the radiation pattern is destroyed, which results in an increase of the SLL and displacement of null positions. In order to regain the symmetry, its mirror sensor weight [w.sub.-7] is forced to zero.