Patent ID: 11876569
Assignee: ASTRAPI CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 0:
1. A method of identifying signal waveforms for signal transmission, comprising:
receiving, via a processor, an input signal, SIGin, comprising signal waveforms
specifying, via a processor, a frequency spectrum range corresponding to the input signal, SIGin,
the frequency spectrum range having a minimum frequency (f_min) and a maximum frequency (f_max);

defining, via the processor, at least one frequency bin within the frequency spectrum range and having a frequency width, f_width and a frequency source, f_source, associated with the frequency bin;
specifying, via the processor, a target intermediate frequency (f_target) for each frequency bin;
identifying, via the processor, a time interval between signal samples, dt;
calculating, via the processor, a sampling frequency, Fs=1/dt and a signal sample length, sig_len;
defining, via the processor, for each frequency bin, a software intermediate frequency bandpass filter, ifbpf, in terms of Fs, f_target, and f_width;
defining, via the processor, an input signal software bandpass filter, INbf, to remove frequencies outside of the frequency spectrum range;
receiving, via the processor, the input signal, SIGin having power distributed over a signal frequency range;
applying, via the processor, the input signal software bandpass filter, INbf, to the input signal, SIGin to produce a filtered input signal;
normalizing, via the processor, the filtered input signal to produce a normalized signal power, SIGin_norm;
storing, via the processor in a memory, the normalized signal power, SIGin_norm;
calculating, via the processor, for each frequency bin, a mixing frequency, f_mix, where

f_mix=f_source−f_target;

calculating, via the processor, for each frequency bin, a mixing stream, cos_mix, where
cos_mix=cos(0:rads_per_sample:rads_per_signal), where
rads_per_sample=f_mix*dt*2*π, and
rads_per_signal=rads_per_sample*(sig_len-1).

generating, via the processor, for each frequency bin, an intermediate frequency (IF) signal, sig_IF, where
sig_IF=SIGin_norm*cos_mix.

applying, via the processor, for each frequency bin, the bandpass filter, ifbpf, to sig_IF to generate a filtered IF signal, sig_IF_filtered;
calculating, via the processor, for each frequency bin, a bin power, bin_power, in the filtered IF signal, sig_IF_filtered, by summing the square of the amplitudes in sig_IF_filtered and dividing this sum by the time interval;
storing, via the processor and in the memory, for each frequency bin, the bin power;
identifying, via the processor, the frequency bin with the maximum bin_power, max_power_idx;
calculating, via the processor, the occupied bandwidth of the input signal by summing the frequency widths of frequency bins based on the bin power, bin_power, in each frequency bin until a predetermined percentage of the input signal power is reached; and
identifying waveforms for transmission based on the occupied bandwidth of the input signal.