LPF.h File Reference

implements four FIR low-pass filters More...

#include <stdint.h>

Go to the source code of this file.

Functions
uint32_t	sqrt2 (uint32_t s)
	square root More...
void	LPF_Init (int32_t initial, int32_t size)
	Initialize first LPF. More...
int32_t	LPF_Calc (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise1 (void)
void	LPF_Init2 (int32_t initial, int32_t size)
	Initialize second LPF. More...
int32_t	LPF_Calc2 (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise2 (void)
void	LPF_Init3 (int32_t initial, int32_t size)
	Initialize third LPF. More...
int32_t	LPF_Calc3 (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise3 (void)
void	LPF_Init4 (int32_t initial, int32_t size)
	Initialize third LPF. More...
int32_t	LPF_Calc4 (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise4 (void)
void	LPF_Init5 (int32_t initial, int32_t size)
	Initialize fifth LPF. More...
int32_t	LPF_Calc5 (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise5 (void)
void	LPF_Init6 (int32_t initial, int32_t size)
	Initialize Sixth LPF. More...
int32_t	LPF_Calc6 (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise6 (void)
void	LPF_Init7 (int32_t initial, int32_t size)
	Initialize Seventh LPF. More...
int32_t	LPF_Calc7 (int32_t newdata)
	FIR low pass filter. More...
int32_t	Noise7 (void)
int32_t	Median (int32_t newdata)
	Median filter. More...
int32_t	Median5 (int32_t newdata)
	Median filter. More...
int32_t	Median7 (int32_t newdata)
	Median filter. More...
int32_t	Filter (int32_t data)
	60-Hz notch high-Q, IIR filter More...

Detailed Description

implements four FIR low-pass filters

Finite length LPF
1) Size is the depth 2 to 16
2) y(n) = (sum(x(n)+x(n-1)+...+x(n-size-1))/size
3) To use a filter
a) initialize it once
b) call the filter at the sampling rate

Version

from TI-RSLK MAX v1.1

Author

Daniel Valvano and Jonathan Valvano

Copyright

Copyright 2020 by Jonathan W. Valvano, valva.nosp@m.no@m.nosp@m.ail.u.nosp@m.texa.nosp@m.s.edu,

Warning

AS-IS

Note

For more information see http://users.ece.utexas.edu/~valvano/

Date

January 15, 2020

Function Documentation

Filter()

int32_t Filter

(

int32_t

data

)

60-Hz notch high-Q, IIR filter

60-Hz notch high-Q, alpha=0.99, IIR filter, assuming fs=1000 Hz.
y(n) = (256x(n) -503x(n-1) + 256x(n-2) + 498y(n-1)-251y(n-2))/256 (2k sampling)
y(n) = (256x(n) -476x(n-1) + 256x(n-2) + 471y(n-1)-251y(n-2))/256 (1k sampling)

Parameters

data	new ADC data

Returns

result filter output

LPF_Calc()

int32_t LPF_Calc

(

int32_t

newdata

)

FIR low pass filter.

First LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Calc2()

int32_t LPF_Calc2

(

int32_t

newdata

)

FIR low pass filter.

Second LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Calc3()

int32_t LPF_Calc3

(

int32_t

newdata

)

FIR low pass filter.

Third LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Calc4()

int32_t LPF_Calc4

(

int32_t

newdata

)

FIR low pass filter.

Fourth LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Calc5()

int32_t LPF_Calc5

(

int32_t

newdata

)

FIR low pass filter.

fifth LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Calc6()

int32_t LPF_Calc6

(

int32_t

newdata

)

FIR low pass filter.

Sixth LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Calc7()

int32_t LPF_Calc7

(

int32_t

newdata

)

FIR low pass filter.

Seventh LPF, calculate one filter output
Called at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

LPF_Init()

void LPF_Init	(	int32_t	initial,
		int32_t	size
	)

Initialize first LPF.

Initialize first LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

LPF_Init2()

void LPF_Init2	(	int32_t	initial,
		int32_t	size
	)

Initialize second LPF.

Initialize second LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

LPF_Init3()

void LPF_Init3	(	int32_t	initial,
		int32_t	size
	)

Initialize third LPF.

Initialize third LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

LPF_Init4()

void LPF_Init4	(	int32_t	initial,
		int32_t	size
	)

Initialize third LPF.

Initialize fourth LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

LPF_Init5()

void LPF_Init5	(	int32_t	initial,
		int32_t	size
	)

Initialize fifth LPF.

Initialize fifth LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

LPF_Init6()

void LPF_Init6	(	int32_t	initial,
		int32_t	size
	)

Initialize Sixth LPF.

Initialize Sixth LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

LPF_Init7()

void LPF_Init7	(	int32_t	initial,
		int32_t	size
	)

Initialize Seventh LPF.

Initialize Seventh LPF
Set all data to an initial value

Parameters

initial	value to preload into MACQ
size	depth of the filter, 2 to 16

Returns

none

Median()

int32_t Median

(

int32_t

newdata

)

Median filter.

3-wide non recursive Median filter
Called with new data at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

Median5()

int32_t Median5

(

int32_t

newdata

)

Median filter.

5-wide non recursive Median filter
Called with new data at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

Median7()

int32_t Median7

(

int32_t

newdata

)

Median filter.

7-wide non recursive Median filter
Called with new data at sampling rate

Parameters

newdata

new ADC data

Returns

result filter output

sqrt2()

uint32_t sqrt2

(

uint32_t

s

)

square root

Newton's method sqrt

Parameters

s	is an integer

Returns

sqrt(s) is an integer