Applied Signal Processing C55x Library

Re-Use Objects

The Applied Signal Processing (ASP) C55x Library provides a few “object oriented” styled DSP objects or “classes”. These objects are implemented in a C++ style in which the object and all required buffer space is defined and created dynamically. They provide a more natural abstract interface to common objects found in DSP systems. The ASP C55x library defines the interface to these objects, their attributes, and their related methods.

Applied Signal Processing C55x Library – Re-Use Objects
*Object Class*	*Description*

Filtering:
CButter	Butterworth Filters, any order
CButter2ord	Butterworth Filters, 2^nd order
CButterVs	Vectorized Butterworth filters.
CLMS	LMS adaptive filter.

Audio Processing:
CEGate	Energy Gate. Voice Activity Detection.
COutGrd	Output Guard. Monitor signal level and shut off if too large.

DSP Support Functions

The Core of the ASP C55x library is a set of C-Callable hand written assembly functions. The functions are listed in the following tables. Note: <name>^C denotes the function is written in C.

*Applied Signal Processing C55x Library Functions*
*Function*	*Description*

Filtering:
butterDFI^C	Generates Butterworth low pass filter coefficients in cascaded 2^nd order sections
delflt	FIR filter with input signal delay
filter	FIR filtering routine
filterRShift1	FIR filter with Right Shift 1of final output.
FiltUpdate	FIR filter and with automatic circular buffer update.
filter_gain	FIR filter with gain applied to final output.
iir2ndDFI	IIR filtering routine using cascaded 2^nd order sections (Direct Form I)
iir2ordDFI	IIR filtering routine – 2^nd order.
update	Performs circular buffer update
circ_clear	Clears circular buffer
circ_clearC55	Clears circular buffer (C55x Optional buffer architecture)
delay	Updates a circular buffer and returns x(k-delay_val)
delayC55	Updates a circular buffer and returns x(k-delay_val) (C55x Optional buffer architecture)

Signal Sources:
gal	Generates a scaled element of a galois sequence with zero mean
tone	Generates a sinusoid with an adjustable level, frequency and phase

Vector Support:
v_add	Adds two vectors
v_clear	Clears a vector
v_copy	Copies a vector
v_fill	Fills a vector with a scalar value
v_sub	Subtracts two vectors
lDot_n1	q31*q15 Dot product

v_update	Updates a 1xN vector of circular buffers with a 1xN vector of input values
v_dc_block	AC couple N signals
v_iir2nd_s	Filter N signals by a single filter, composed of cascaded IIR 2^nd order sections
v_iir2nd_s_contig	Filter N signals by a single filter, composed of cascaded IIR 2^nd order sections using contiguous X and Y buffer Space
CButterVs_Filter	Filter N signals by a single Butterworth filter descriptor.

Sliding DCT Support:
dcts_xget	Updates a circular buffer and returns M delayed elements from the buffer
dcts	Computes N discrete cosine transform (DCT) IIR filter outputs
CDCT_CalcOddEvenAsm	Calculate the x_odd and x_even terms for the dct difference equation

Freq Sampling Filter:
CFSF2_FilterCalc

*Applied Signal Processing C55x Library Functions (continued)*
*Function*	*Description*

LMS Adapt Support:
CLMS_LMSFiltAdaptUpdate	LMS filter output calculation and update on a buffer of filter coefficients
CLMS_LMSDelFiltAdaptUpdate	LMS filter output calculation update on a buffer of filter coefficients with input buffer delay
CLMS_NLMSDelFiltAdaptUpdate	Normalized LMS filter output calculation update on a buffer of filter coefficients with input buffer delay
CLMS_NLMSFiltAdaptUpdate	Normalized LMS filter output calculation and update on a buffer of filter coefficients

Expanded Instrinics:
_bit	Test a bit
l_EXP	Get the normalization shift of a long integer.
l_NormShift	Arithmetic shift of long argument via the NORM instruction
l_NormLongPair	Normalize a pair of long integers

Math Support:
QZ_QMULTOVUN(x,y,QZ,QX,QY)	Generalize Mixed Q operand multiplication MACRO with OVERFLOW and UNDERFLOW protection. Will generate call to one of several possible ASM Q math functions
qz_QMultOVPosShiftGEQ8	QZ_QMULTOVUN support function
qz_QMultOVPosShiftLT8	QZ_QMULTOVUN support function
qz_QMultNegShiftUN	QZ_QMULTOVUN support function
qz_QMultOVPosShift	QZ_QMULTOVUN support function
qz_QMultOVUN	Generalize Mixed Q operand multiplication with OVERFLOW and UNDERFLOW protection.
qz_QMultOV	Generalize Mixed Q operand multiplication with OVERFLOW protection

qx_NormDivide	Normalized divide of two 32 bit numbers, returned as desired Q type.
qx_NormDivideNoRnd	Normalized divide of two 32 bit numbers without rounding, returned as desired Q type
long_q16_DivideQx	Returns the long result of dividing two 16 bit numbers
qx_Divide	Divide two number and return as desired Q type
int_DivideRnd	Integer division with rounding.
int_Divide	Integer division without rounding.
q15_InverseInt	Invert an Integer
qx_InverseQ15	Invert a q15 number, return as desired Q type.

q15_sqrt	Take square root of a Q15 number
sin_taylor	Taylor Series Expansion estimate of sin(x)
q15_pow_q4exp	Raises x to the fractional power y, z = q15_x^(q4_y)

Other Re-Use Objects & Components Available

ASP has developed a variety of other software components for a variety of C55x applications. These modules and objects are currently not part of the ASP C55x library, but could customized and/or generalized for use in any DSP system. Components that follow the object oriented implementation style are identified with the C<name> identifier.

*Applied Signal Processing* – *Software Components & Re-Use Objects*
*Component*	*Description*

Filtering:
CNotch2ord	2^nd Order Notch Filter

Audio Processing:
CFSF	Frequency Sampling Filter Bank. Splits signal into N frequency bands
CDCT	Sliding Discrete Cosine Transform Object. Splits signal into N frequency bands
CToneSeq	Tone Sequence Object – Defines and plays a given tone sequence of various frequencies and durations.
FBDetSuppress	Feedback Detection and Suppression
MSwitch	Microphone Switch – detects voice activity and selects a channel from an array of channels.
NRA	Noise Reduction Algorithm – Cleans up speech signals
Spd_Comp	Generalized Speed Compensated Parameter (Volume, Equalization, etc)
Compressor	Audio Compressor with Downward Expansion, Linear, Compression and Limit Regions

Fault Reporting:
CDiagMsg	Diagnostic Message Objects and Handling
CFault	Fault Reporting and Logging Object
CEventRecord	Diagnostic Event Object

General OS:
CQue	FIFO Queue
Mem	Pseudo Dynamic memory allocation with multiple memory heaps

Data Acquisition:
CTraceChannel	Data Acquisition Channel – Playback/record any variable to/from a large memory buffer.
CTraceBuffer	Trace Buffer Object – synchronously playback/record several channels to/from a large memory buffer.

Misc:
ParameterSector	Reads/Writes system parameters from/to a flash device.
PRB	Software Probes – probe any variable and optionally send its value to an Auxiliary Analog Output Channel.

Other DSP Support Functions Available

Applied Signal Processing has developed a variety of other C-Callable assembly functions for a variety of C55x applications. These functions are currently not part of the ASP C55x library, but can be added to a custom built C55x library if so desired.

*Applied Signal Processing* – *Other ASM Functions*
*Function*	*Description*

Filter Support:
v_dc_block32	DC Blocking filter with 32 bit recursive data path. Good for extremely small Fc/Fs ratios.
q31_iir2ordDFI	2^nd order IIR filter, returns a 32 bit result.

Vector Support:
lv_mag_avg_shft	Calculates the 32 bit average magnitude of N time domain signals on a sample by sample basis using a forgeting factor.
llv_mag_avg	Calculates the 32 bit average magnitude of N 32 bit time domain signals on a sample by sample basis using a forgeting factor.
ll_maxvec	Behaves like the matlab [maxval,Index]=max( ) function. It takes a vector of longs as inputs and returns the maxval and maxindex.

Math Support:
q31 q15q31mult(q31 x, q15 y)	q15 x q31 multiply as q31
q31 q15q31mult1(q31* x, q15* y)	q15 x q31 multiply as q31
q31 q15q31mult2(q31* x, q15 y)	q15 x q31 multiply as q31

Misc:
gal31	31 bit galois sequence random noise generator.
CLookup_GetMappedParameter^C	Lookup Table Implementation – maps a parameter Y to value X

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