HD6433044 Datasheet, PDF (530/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

The receive margin can therefore be expressed as follows.
Receive margin in smart card mode:
1
M = | 0.5 –
2N
– (L – 0.5) F –
| D – 0.5 |
N ^{(1 + F) | × 100%}
M: Receive margin (%)
N: Ratio of clock frequency to bit rate (N = 372)
D: Clock duty cycle (D = 0 to 1.0)
L: Frame length (L = 10)
F: Absolute deviation of clock frequency
From this equation, if F = 0 and D = 0.5 the receive margin is as follows.
D = 0.5, F = 0
M = {0.5 – 1/(2 × 372)} × 100%
= 49.866%
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