You need the Xtal only when you want to have the date/time displayed correctly.
Jos
Op 25-3-2021 om 09:43 schreef Rui Valente:
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Hello
I installed the latest version 1.0.50 and i solder a new SD card
slot...them i tested 3 different sd card and different capacities but
anything happen in the menu sd card (no error message) after i remove the
cards and theyare empty...is necessary install the 32khz cristal ? I don't
install yet...
Thanks in advance...
73 CT2GGX
A quinta, 25/03/2021, 03:59, DiSlord <dislordlive@...> escreveu:
I fix one problem in DSP code (for H version) in 1.0.50.
H4 use DSP instruction and more faster/accurate in calculations
DSP code for H:
do{
int16_t ref = capture[i+0];
int16_t smp = capture[i+1];
int32_t sin = ((int16_t *)sincos_tbl)[i+0];
int32_t cos = ((int16_t *)sincos_tbl)[i+1];
samp_s+= (smp * sin)/16;
samp_c+= (smp * cos)/16;
ref_s += (ref * sin)/16;
ref_c += (ref * cos)/16;
i+=2;
}while (i < length);
Yes /=16 used for prevent overflow on int32 values
Code for H4:
do{
int32_t sc = ((int32_t *)sincos_tbl)[i];
int32_t sr = ((int32_t *)capture)[i];
// int64_t acc DSP functions
acc_samp_s= __smlaltb(acc_samp_s, sr, sc ); // samp_s+= smp * sin
acc_samp_c= __smlaltt(acc_samp_c, sr, sc ); // samp_c+= smp * cos
acc_ref_s = __smlalbb( acc_ref_s, sr, sc ); // ref_s+= ref * sin
acc_ref_c = __smlalbt( acc_ref_c, sr, sc ); // ref_s+= ref * cos
i++;
} while (i < length/2);
It use int64 accumulator (it aslo used for accumulate for
average/bandwidth) and one instruction for calculate (H can`t fast
processing measured data in int64)
On H4 i can get up to - 100 - 110dB dynamic range on measure S21 in 1 to
100MHz
