Tool to convert VLBI VDIF format to complex floats

vdif_convert.py

#!/usr/bin/env python3
import os
import sys
import argparse

import numpy as np

import baseband

import astropy.units as u

if __name__ == "__main__":
    # Read command line arguments
    parser = argparse.ArgumentParser(description="Convert VDIF VLBI format to complex floats")
    parser.add_argument("file", help="Input VDIF file",
                        metavar="FILE")
    parser.add_argument("-l", "--length", help="Time length to extract [seconds; defaul: 1.0]", type=float,
                        default=1.0)
    args = parser.parse_args()

    
    # Arguments logic
    if not os.path.exists(args.file):
        print(f"{args.file} not found.")
        sys.exit()
    
    # Open file
    fp = baseband.open(args.file)

    # Read parameters
    tstart = fp.start_time
    samp_rate = fp.sample_rate.to(u.Hz).value
    tsamp = 1.0 / samp_rate
    bw = 0.5 * samp_rate * 1e-6 # in MHz
    
    # Read data file
    nsamp = int(args.length / tsamp)
    data = fp.read(nsamp)

    # Write out results
    tstr = fp.start_time.isot
    fname = f"DBBC_{tstr}_1575.000MHz_{samp_rate * 1e-6:.3f}Msps_RCP_RT0_real.raw"
    data[:, 0].tofile(fname)
    fname = f"DBBC_{tstr}_1575.000MHz_{samp_rate * 1e-6:.3f}Msps_LCP_RT0_real.raw"
    data[:, 1].tofile(fname)

    # Close input file
    fp.close()