/*The data contained in directory "syowa" are made available by 

               Prof. Katsutada Kaminuma
               Department of  Earth Sciences 
               National Institute of Polar Research
               1-9-10 Kaga, Itabashi-ku, Tokyo 173, Japan
               Fax:81(Japan)-3-3962-5741
               Tel:81-3-3962-4711 Ext.354

The coordinates for SYO (Syowa) Station are
               69deg 00min 31.7sec S, 39deg 35min 31.6sec E

Syowa                         Antarctica                    SYO*  
       -69.01    39.59     Pre-POSEIDON        Existing       VBB,140dB


-----------Do you want to use other data at SYO station?----------------

All the arrivals read at this station are listed in JARE DATA REPORTS,
Japanese Antarctic Research Expedition, National Institute of Polar
Research, Tokyo, Japan. For example, No.172 published in Feb 1992. Please
first refer this report when you would like to use other event data.
After you confirm that the event was recorded at this station, please
write to Prof. Kaminuma specifically which data you would like to use.
Then Prof. Kaminuma will send the data to us, Pre-POSEIDON Data Center.
Then we can transfer the data to this directory and make them available 
to users.

-----------Do you want to decode the data?------------------------------

Following is a C program to decode the SYOWA data.
Please distribute this to anyone who may be interseted in.

*	rd_soywa.c
*
*	program to decode SYOWA STS1 data with 10Hz sampling
*
*	each record contains 178 bytes binary data corresponding
*	three components seismograms for one second (i.e., 30 data points)
*
*	as for decoding, refer to the QUANTERRA manual
*
*	Nov. 20, 1992   coded by H. Kawakatsu  
*	                        (Earthquake Reserch Institue, U. Tokyo)
*
* USAGE:
*	rd_syowa.x < data_file > out_file
*	data will be printed in ascii
*/
#include <stdio.h>

struct syowa {
	unsigned char p[3][3],uc,s[30][5],cc[18];
}  data; 

struct gram  {
	int year,month,day,hour,min,sec;
	int pos[3],seis[3][10];  
		/*	
		 *	seis[0]: Z
		 *	seis[1]: N
		 *	seis[2]: E
		 */
}  sgram;

rd_syowa_(ndr,iyy,imon,iday,ih,im,isec,wavez,waven,wavee)
    int *iyy,*imon,*iday,*ih,*im,*isec;
    long *ndr;
    float wavez[],waven[],wavee[];
{
int i,n=0;
/*printf("        Z          N          E\n\n");  */
fseek(stdin,0L,2);
printf("%ld \n",ftell(stdin));
*ndr=ftell(stdin)/178*10;
printf("npts= %ld\n",*ndr);
fseek(stdin,0L,0);
while( n< *ndr) 
{
fread(&data,178,1,stdin);
decode();

if(n==0)
{printf("%2d %2d %2d %2d %2d %2d\n",
	sgram.year,sgram.month,sgram.day,sgram.hour,sgram.min,sgram.sec); 
*iyy=sgram.year; 
*imon=sgram.month; 
*iday=sgram.day; 
*ih=sgram.hour;
*im=sgram.min; 
*isec=sgram.sec; 
}
/*
fprintf(stderr,"%2d %2d %2d %2d %2d %2d\n",
	sgram.year,sgram.month,sgram.day,sgram.hour,sgram.min,sgram.sec); */

/*
printf("POS: %10d %10d %10d\n",sgram.pos[0],sgram.pos[1],sgram.pos[2]);
*/
for(i=0;i<10;i++,n++)  
	{
/*	printf("%10d %10d %10d\n",sgram.seis[0][i],sgram.seis[1][i],sgram.seis[2][i]); 
*/
        wavez[n]=(double)sgram.seis[0][i];
        waven[n]=(double)sgram.seis[1][i];
        wavee[n]=(double)sgram.seis[2][i];
/*
	printf("%5d %10d %10d %10d\n",n,sgram.seis[0][i],sgram.seis[1][i],sgram.seis[2][i]);
*/
	}
   }
}

decode()
{
int  i,isg[3],icomp;
short conv_p();
unsigned char iuc, conv_uc();

for(i=0;i<3;i++)
{
sgram.pos[i] = conv_p(data.p[i]);
isg[i]=0;
}

iuc = conv_uc(data.uc);

for(i=0;i<30;i++)
	{
	icomp = data.s[i][4]&07;
	sgram.seis[icomp][isg[icomp]++] = conv_sg(data.s[i]);
	}

sscanf(data.cc,"%2d%2d%2d%2d%2d00%2d",&sgram.hour,&sgram.min,&sgram.day,&sgram.month,&sgram.year,&sgram.sec);
}	


conv_sg(ss)
unsigned char ss[5];
{
unsigned char c1,c2,c3;
int  dum,dum2;

c1 = ss[3]<<6;
c2 = ((ss[3]>>2)<<6);
c3 = ((ss[3]>>4)<<6);

dum =  ss[2] + c1;
dum += (ss[1] + c2) *256;
dum += (ss[0] + c3) *65536;

/* convet 24-bit 2's complement interger*/
if( (dum>>23)&01 )
  {
  dum2 = (~dum + 1) & 077777777;
/*
  printf("neg  %10d  %10d  %10d\n",dum2,dum,(dum+dum2)&077777777);
*/
  dum = -dum2;
  }
/*
else
  {
  printf("pos  %10d\n",dum);
  }
*/

return(dum);
}

short conv_p(pp)
unsigned char pp[3];
{
short dum;

dum = (pp[2]>>1);
dum += (pp[1]<<5);
dum += (pp[0]<<11);

return(dum);
}

unsigned char conv_uc(uc)
unsigned char uc;
{
unsigned char dum;

dum = (uc<<2)>>5;
return(dum);
}