88 lines
3.9 KiB
C
88 lines
3.9 KiB
C
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/*
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* bell202.h
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*
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* Copyright (c) 2005 Robert Krten. All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This module contains the manifest constants and declarations for
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* the Bell-202 1200 baud FSK modem.
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*
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* 2005 03 20 R. Krten created
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*/
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#ifndef __BELL202_H__
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#define __BELL202_H__
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typedef struct dsp_bell202_attr_s
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{
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int sample_rate; // sample rate in HZ
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void (*bithandler) (void *, int); // bit handler
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void *bithandler_arg; // arbitrary ID passed to bithandler as first argument
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void (*bytehandler) (void *, int); // byte handler
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void *bytehandler_arg; // arbitrary ID passed to bytehandler as first argument
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} dsp_bell202_attr_t;
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typedef struct
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{
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dsp_bell202_attr_t attr; // attributes structure
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double *correlates [4]; // one for each of sin/cos for mark/space
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int corrsize; // correlate size (also number of samples in ring buffer)
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double *buffer; // sample ring buffer
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int ringstart; // ring buffer start offset
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double cellpos; // bit cell position
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double celladj; // bit cell adjustment for each sample
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int previous_bit; // previous bit (for detecting a transition to sync-up cell position)
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int current_bit; // current bit
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int downsampling_count; // number of samples to skip
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int current_downsample; // current skip count
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} dsp_bell202_handle_t;
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/*
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* Function prototypes
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*
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* General calling order is:
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* a) create the attributes structure (dsp_bell202_attr_init)
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* b) initialize fields in the attributes structure (dsp_bell202_attr_set_*)
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* c) create a Bell-202 handle (dsp_bell202_create)
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* d) feed samples through the handler (dsp_bell202_sample)
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*/
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extern void dsp_bell202_attr_init (dsp_bell202_attr_t *attributes);
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extern void (*dsp_bell202_attr_get_bithandler (dsp_bell202_attr_t *attributes, void **bithandler_arg)) (void *, int);
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extern void dsp_bell202_attr_set_bithandler (dsp_bell202_attr_t *attributes, void (*bithandler) (void *, int ), void *bithandler_arg);
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extern void (*dsp_bell202_attr_get_bytehandler (dsp_bell202_attr_t *attributes, void **bytehandler_arg)) (void *, int);
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extern void dsp_bell202_attr_set_bytehandler (dsp_bell202_attr_t *attributes, void (*bytehandler) (void *, int ), void *bytehandler_arg);
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extern int dsp_bell202_attr_get_samplerate (dsp_bell202_attr_t *attributes);
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extern int dsp_bell202_attr_set_samplerate (dsp_bell202_attr_t *attributes, int samplerate);
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extern dsp_bell202_handle_t * dsp_bell202_create (dsp_bell202_attr_t *attributes);
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extern void dsp_bell202_destroy (dsp_bell202_handle_t *handle);
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extern void dsp_bell202_sample (dsp_bell202_handle_t *handle, double normalized_sample);
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#endif // __BELL202_H__
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