public void CalcSpectrum(int filter_low, int filter_high, int spec_blocksize, int sample_rate)
{
//filter_low is the low frequency setting for the filter
//filter_high is the high frequency setting for the filter
//samplerate is the current samplerate
//fft_size is the current FFT size
//no spur elimination => only one spur_elim_fft and it's spectrum is not flipped
int[] flip = { 0 };
GCHandle handle = GCHandle.Alloc(flip, GCHandleType.Pinned);
IntPtr h_flip = handle.AddrOfPinnedObject();
// const int extra = 1000;
//if we allow a little extra spectrum to be displayed on each side of
// the filter settings, then, you can look at filter rolloff. This
// seems to happen at least some of the time with the old spectrum display.
// "extra" is the amount extra to leave on each side of the filter bandwidth
// and is in Hertz.
//the upper and lower limits of the displayed spectrum would be
int upper_freq = filter_high; // +extra;
int lower_freq = filter_low; // -extra;
//bandwidth to clip off on the high and low sides
double high_clip_bw = 0.5 * sample_rate - upper_freq;
double low_clip_bw = 0.5 * sample_rate + lower_freq;
//calculate the width of each frequency bin
double bin_width = (double)sample_rate / fft_size;
//calculate span clip parameters
int fsclipH = (int)Math.Floor(high_clip_bw / bin_width);
int fsclipL = (int)Math.Ceiling(low_clip_bw / bin_width);
//no need for any symmetrical clipping
int sclip = 0;
int stitch = 1;
max_w = fft_size + (int)Math.Min(KEEP_TIME * sample_rate, KEEP_TIME * fft_size * frame_rate);
Display.RXSpectrumDisplayLow = lower_freq;
Display.RXSpectrumDisplayHigh = upper_freq;
// set overlap as needed to achieve the desired frame rate
overlap = (int)Math.Max(0.0, Math.Ceiling(fft_size - (double)sample_rate / (double)frame_rate));
SpecHPSDRDLL.SetAnalyzer(
disp,
2,
spur_eliminationtion_ffts,
data_type,
h_flip,
fft_size,
spec_blocksize,
window_type,
kaiser_pi,
overlap,
sclip,
fsclipL,
fsclipH,
pixels,
stitch,
calibration_data_set,
span_min_freq,
span_max_freq,
max_w);
}
public void initAnalyzer()
{
//no spur elimination => only one spur_elim_fft and it's spectrum is not flipped
int[] flip = { 0 };
GCHandle handle = GCHandle.Alloc(flip, GCHandleType.Pinned);
IntPtr h_flip = handle.AddrOfPinnedObject();
int low = 0;
int high = 0;
int low_tx = 0;
int high_tx = 0;
double bw_per_subspan = 0.0;
double bw_per_subspan_tx = 0.0;
switch (data_type)
{
case 0: //real fft - in case we want to use for wideband data in the future
{
break;
}
case 1: //complex fft
{
//fraction of the spectrum to clip off each side of each sub-span
const double CLIP_FRACTION = 0.017;
//set overlap as needed to achieve the desired frame_rate
overlap = (int)Math.Max(0.0, Math.Ceiling(fft_size - (double)sample_rate / (double)frame_rate));
//clip is the number of bins to clip off each side of each sub-span
clip = (int)Math.Floor(CLIP_FRACTION * fft_size);
//the amount of frequency in each fft bin (for complex samples) is given by:
double bin_width = (double)sample_rate / (double)fft_size;
double bin_width_tx = 96000.0 / (double)fft_size;
//the number of useable bins per subspan is
int bins_per_subspan = fft_size - 2 * clip;
//the amount of useable bandwidth we get from each subspan is:
bw_per_subspan = bins_per_subspan * bin_width;
bw_per_subspan_tx = bins_per_subspan * bin_width_tx;
//the total number of bins available to display is:
int bins = stitches * bins_per_subspan;
//apply log function to zoom slider value
double zoom_slider = Math.Log10(9.0 * z_slider + 1.0);
//limits how much you can zoom in; higher value means you zoom more
const double zoom_limit = 100;
int width = (int)(bins * (1.0 - (1.0 - 1.0 / zoom_limit) * zoom_slider));
//FSCLIPL is 0 if pan_slider is 0; it's bins-width if pan_slider is 1
//FSCLIPH is bins-width if pan_slider is 0; it's 0 if pan_slider is 1
span_clip_l = (int)Math.Floor(pan_slider * (bins - width));
span_clip_h = bins - width - span_clip_l;
if (Display.RX1DSPMode == DSPMode.DRM)
{
//Apply any desired frequency offset
int bin_offset = (int)(freq_offset / bin_width);
if ((span_clip_h -= bin_offset) < 0)
{
span_clip_h = 0;
}
span_clip_l = bins - width - span_clip_h;
}
//As for the low and high frequencies that are being displayed:
low = -(int)((double)stitches / 2.0 * bw_per_subspan - (double)span_clip_l * bin_width + bin_width / 2.0);
high = +(int)((double)stitches / 2.0 * bw_per_subspan - (double)span_clip_h * bin_width - bin_width / 2.0);
low_tx = -(int)((double)stitches / 2.0 * bw_per_subspan_tx - (double)span_clip_l * bin_width_tx + bin_width_tx / 2.0);
high_tx = +(int)((double)stitches / 2.0 * bw_per_subspan_tx - (double)span_clip_h * bin_width_tx - bin_width_tx / 2.0);
//Note that the bin_width/2.0 factors are included because the complex FFT has one more negative output bin
// than positive output bin.
max_w = fft_size + (int)Math.Min(KEEP_TIME * sample_rate, KEEP_TIME * fft_size * frame_rate);
break;
}
}
switch (disp)
{
case 0:
Display.RXDisplayLow = low;
Display.RXDisplayHigh = high;
if (Display.CurrentDisplayMode == DisplayMode.WATERFALL ||
Display.CurrentDisplayMode == DisplayMode.PANAFALL)
{
Display.TXDisplayLow = low_tx;
Display.TXDisplayHigh = high_tx;
}
break;
case 1:
Display.RX2DisplayLow = low;
Display.RX2DisplayHigh = high;
if (!(Display.CurrentDisplayMode == DisplayMode.WATERFALL ||
Display.CurrentDisplayMode == DisplayMode.PANAFALL))
{
Display.TXDisplayLow = low_tx;
Display.TXDisplayHigh = high_tx;
}
break;
}
JanusAudio.LowFreqOffset = bw_per_subspan;
JanusAudio.HighFreqOffset = bw_per_subspan;
if (disp == 0)
{
if (Display.CurrentDisplayMode != DisplayMode.PANADAPTER &&
Display.CurrentDisplayMode != DisplayMode.WATERFALL &&
Display.CurrentDisplayMode != DisplayMode.PANAFALL &&
Display.CurrentDisplayMode != DisplayMode.PANASCOPE)
{
return;
}
}
SpecHPSDRDLL.SetAnalyzer(
disp,
2,
spur_eliminationtion_ffts,
data_type,
h_flip,
fft_size,
blocksize,
window_type,
kaiser_pi,
overlap,
clip,
span_clip_l,
span_clip_h,
pixels,
stitches,
calibration_data_set,
span_min_freq,
span_max_freq,
max_w);
}