Output Signal

Technical Note of Magnetic Pattern Recognition Sensors
- Sensor Output Signal Models -

Magnetic differentiation sensors detect patterns on target media and their magnetic intensity.

Bank Note Trace Model
Bank Note Trace Model

E13B Character Trace Model
E13B Character Trace Model

- Element Pitch and Output Signal -

Resolution depends on the element pitch.

1. With standard detecting elements, a circuit is created with two elements mounted on a single chip.

Dimensions of Standard Elements
Dimensions of Standard Elements

  1. The elements are designed according to the dimensions of the patterns on the target media and the purpose of detection.
  2. To detect dense patterns, reduce the element pitch (0.75mm). To detect wide patterns, increase the detecting width (3mm).
  3. The thickness and quality of the substrate is selected to optimize the magnetic circuit.

2. Pitch of magnetic media and output characteristics

Pitch of magnetic media and output characteristics

  • The sensor's detecting width is 3mm, element pitch is 0.75mm, and element width is 0.3mm.
  • The detected media are magnetic ink patterns with low coercivity.

    1. When the pattern pitch is "p" and the element pitch is p/2, the SN ratio becomes the maximum value. For example, when the element pitch is 0.75, the pattern pitch is 1.5mm.
    2. When the pattern pitch is reduced to 0.7mm, the resolution is decreased.
    3. When the pattern pitch is reduced to 0.5mm or less, the sensor recognizes two separate patterns as one, but the magnetic intensity of the two patterns is still measured.

pattern pitch

- Detecting Width and Output Signal -

The detecting width depends on the element length.

    1. With standard models, detecting widths of 3mm, 6mm, and 10mm are available. A detecting width of 20mm or less can be provided for custom-made models.
    2. When a magnetic medium with 3-mm width passes over the sensor with 3-mm detecting width, the output voltage for the pattern displaced from the center of the sensor by 1.5mm is approximately half the output voltage of the pattern passing the center of the sensor. If the pattern is displaced from the center of the sensor by 3mm, the sensor does not detect the pattern. The sensor with 6-mm detecting width can detect the pattern, even if it is displaced from the center of the sensor by 3mm.
    3. If the sensor with 6-mm detecting width detects a medium with 3-mm width, the output of this sensor is approximately half that of the sensor with 3-mm detecting width. This is because the magnetic field affecting the sensor with 6-mm width is halved relative to the element length.

the element length

Output Characteristic 1
Output Characteristic 2
Output Characteristic 1 for
Detection of Displaced Pattern
Output Characteristic 2 for
Detection of Displaced Pattern