Freescale Semiconductor, Inc.
PLL Tuned UHF Transmitter Module
16.7.3 Internal Manchester Coding
When using the Manchester internal coding feature (Figure 16-5), these
two comments should be noted:
1. Due to the XOR operation performed, any delay between MODE
and DATA negative edges generates glitches at the XOR output.
These glitches are filtered by an internal low-pass filter before
reaching the modulation stage. The amount of spurious radiation
at the RF output depends on this delay.
2. The Manchester signal duty cycle depends on the position of the
MODE positive edge relative to DATA. Deviation from the
50 percent value will result in an average amplitude different
from 0. Generally, avoid this.
To achieve the best performances, these timings should be carefully
controlled by the user.
UPCLK
PLL
PLLEN
MODE
OOK
SELECT
DATA
RF OUT
SUPPLY CURRENT
(NOT SCALED)
Figure 16-5. Internal Manchester Coding Feature
Advance Information
228
MC68HC908RFRK2
PLL Tuned UHF Transmitter Module
MOTOROLA
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