dco

Capsim Block Documentation

Short Description

This star produces samples of the outputs every 1/fs seconds. The dco behaves just like an FM modulator. The phase is updated as theta=theta+lambda (integrates the input)

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Input Connections
Port Type Name
0 float lambda
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Output Connections
Port Type Name
0 float cout
1 float sout
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Parameters
Num Description Type Name Default Value
0 Sampling Rate float fs 1.
1 Center Frequency float fo 1.
2 Amplitude float A 1.
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States
Num Type Name Initial Value Description
0 int t 0.
1 float theta 0.
2 float dt 0
3 double angle 0
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Declarations


 

	float	lambdax;
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Initialization Code



 

	dt = 2.*PI*fo/fs;
	angle= -dt;
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Main Code



 


	while(IT_IN(0))
	{
		if(IT_OUT(0)) {
			KrnOverflow("dco",0);
			return(99);
		}
		if(IT_OUT(1)) {
			KrnOverflow("dco",1);
			return(99);
		}
		
		
		lambdax=lambda(0);
		angle= angle +dt+lambdax;
		angle=fmod(angle,PI2);
		
		

		cout(0)=A*cos((angle));
		sout(0)=A*sin((angle));
		
	}
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Wrapup Code
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License



/*  Capsim (r) Text Mode Kernel (TMK) Star Library (Blocks)
    Copyright (C) 1989-2002  XCAD Corporation 

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    http://capsimtmk.sourceforge.net
    XCAD Corporation
    Raleigh, North Carolina */
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Description



 

/*								*

dco


 *	dco.s	:	digitally controlled oscillator 		*
 *									*
 *	parameters:	fs, sampling frequency				*
 *			fo, center frequency				*
 *			A, amplitude					*
 *									*
 *	inputs:		lambda, phase update term			*
 *									*
 *	outputs:	A*cos(2*PI*fo*t+theta)				*
 *			A*sin(2*PI*fo*t+theta)				*
 *									*
 *	description:	This star produces samples of the outputs	*
 *			every 1/fs seconds.  The dco behaves just	*
 *			like an FM modulator.  The phase is updated	*
 *			as theta=theta+lambda (integrates the input)	*
 *	


written by John T. Stonick

*/