PIC18LF24K Datasheet, PDF (318/594 Pages) –

PIC18(L)F26/45/46K40
25.0 DATA SIGNAL MODULATOR
(DSM) MODULE
The Data Signal Modulator (DSM) is a peripheral which
allows the user to mix a data stream, also known as a
modulator signal, with a carrier signal to produce a
modulated output.
Both the carrier and the modulator signals are supplied
to the DSM module either internally, from the output of
a peripheral, or externally through an input pin.
The modulated output signal is generated by
performing a logical “AND” operation of both the carrier
and modulator signals and then provided to the MDOUT
pin.
The carrier signal is comprised of two distinct and
separate signals. A carrier high (CARH) signal and a
carrier low (CARL) signal. During the time in which the
modulator (MOD) signal is in a logic high state, the
DSM mixes the carrier high signal with the modulator
signal. When the modulator signal is in a logic low
state, the DSM mixes the carrier low signal with the
modulator signal.
Using this method, the DSM can generate the following
types of Key Modulation schemes:
• Frequency-Shift Keying (FSK)
• Phase-Shift Keying (PSK)
• On-Off Keying (OOK)
Additionally, the following features are provided within
the DSM module:
• Carrier Synchronization
• Carrier Source Polarity Select
• Programmable Modulator Data
• Modulated Output Polarity Select
• Peripheral Module Disable, which provides the
ability to place the DSM module in the lowest
power consumption mode
Figure 25-1 shows a Simplified Block Diagram of the
Data Signal Modulator peripheral.
 2016 Microchip Technology Inc.
Preliminary
DS40001816C-page 318