Imported from GitHub: Gosharad1980/DistributedPulseModulation · commit 6804fab · license CC-BY-SA-4.0

Description

Distributed pulse modulation done, with KiCad 9, like with the old P82C150, but with descrete components

README

DistributedPulseModulation

Distributed pulse modulation done like with the old P82C150, but with descrete components

Theory of operation

With a regular Pulse Width Modulation (PWM), all the pulses are grouped in a same and unique pulse over the whole period. On Distributed Pulse Modulation (DPM) and Dyadic Descrete Pulse Modulation (DDPM), the aim is to distribute all the "sub-pulses" throughout the whole period.

Two advantages :

• spectrum with more high frequencies than PWM : easier filtering in case of A/D conversion
• as the pulse distribution is continuously evaluated : a threshold modification, before the period end, is taken into account without delay

Old P82C150 for DPM implementation

P82C150 - Application note

P82C150 datasheet

DDPM implementation based on Paolo S. Crovetti thesis

Thèse : Paolo S. Crovetti

The breakout board

Features

PWM (Pulse Width Modulation)
DPM P82C150-like (Distributed Pulse Modulation)
DDPM (Dyadic Discrete Pulse Modulation)

Photographies done with the PCB_V1.0 board

MCP23017 Port A & B

MCP23017 is an I2C 16bits IO expander
Port A & B are used to control the board
Prescaler decoding values :
0x00	1
0x01	2
0x02	8
0x03	16
0x04	64
0x05	256
0x06	1024
0x07	4096

Board configurations (PCB_V2.0)

PWM

• do not populate the CD74HCT4053
• place the jumpers as describe in the silkscreen schematic (PWM)

DPM

• do not populate the CD74HCT4053
• place the jumpers as describe in the silkscreen schematic (DPM/DDPM)

DDPM

• do not populate the 74LS85
• place the jumpers as describe in the silkscreen schematic (DPM/DDPM)