PCT datatypes

C M pynasonde.vipir.riq.datatypes.pct — Ionogram, PctType dataclasses and to_mantissa_exponant helper.

Dataclasses modeling VIPIR PCT-format data blocks.

pynasonde.vipir.riq.datatypes.pct

PCT (pulse capture table) datatypes and binary readers for VIPIR/RIQ.

This module defines small dataclasses used to hold per-PRI (PCT) information as well as helper routines to decode packed IQ formats found in VIPIR binary dumps. The reader method on :class:PctType consumes binary data from a file-like object and populates the structure according to the VIPIR configuration and the SCT (station) type information.

Ionogram dataclass

Container for decoded ionogram arrays.

Attributes:

Name	Type	Description
pulse_i		numpy.ndarray In-phase samples (shape: gates x receivers).
pulse_q		numpy.ndarray Quadrature samples (shape: gates x receivers).
power		numpy.ndarray Linear power values per gate/receiver.
powerdB		numpy.ndarray Power in dB / SNR per gate/receiver.
phase		numpy.ndarray Phase for each gate/receiver.
frequency		numpy.ndarray Frequencies for each pulse set.
height		numpy.ndarray Heights for each range gate.

PctType dataclass

Representation of a single PCT (per-PRI) record.

Attributes:

Name	Type	Description
record_id		numpy.int32 Sequence number of this PCT.
pri_ut		numpy.float64 Universal Time of this pulse.
pri_time_offset		numpy.float64 Local time offset read from the system clock (not precise).
base_id		numpy.int32 Base frequency counter value.
pulse_id,	ramp_id, repeat_id, loop_id	numpy.int32 Indices describing the pulse/ramp/repeat/loop position of this PRI.
frequency		numpy.float64 Observation frequency (kHz).
nco_tune_word		numpy.int32 Hardware tuning word.
drive_attenuation		numpy.float64 Drive attenuation in dB.
proc_range_count		numpy.int32 Number of range gates processed for this PRI.
proc_noise_level		numpy.float64 Estimated noise level for this PRI.
user		str Spare text field (user-defined, fixed-width in file).

fix_PCT_strings()

Normalize fixed-width string fields by trimming nulls.

The VIPIR binary stores ASCII fields in fixed-width slots which may include trailing null characters; this helper trims those trailing nulls into Python strings.

read_pct_from_file_pointer(fp, sct, vipir_config, unicode='latin-1')

Read PCT data from a binary file pointer into this object.

The method reads header fields according to PCT_default_factory using :func:read_dtype, then consumes the IQ payload for the PRI and decodes it according to vipir_config.data_type.

Parameters:

Name	Type	Description	Default
fp		file-like Open binary file-like object positioned at the start of the PCT payload.	required
sct		SctType Station configuration describing receiver counts and gate counts.	required
vipir_config		types.SimpleNamespace VIPIR configuration object with fields like vipir_version, data_type and np_format describing the binary layout.	required
unicode		str, optional Encoding used when reading textual fields (default 'latin-1').	'latin-1'

Returns:

Type	Description
	Returns self after populating the fields and IQ arrays.

dump_pct(t32=1.86264514923096e-05, to_file=None)

Format the PCT record into a human-readable text block.

Parameters t32 : numpy.float64, optional Scale factor used for printing tuned words (present for diagnostic purposes). to_file : str or None, optional If provided, write the text to the given filename. Otherwise the formatted text is emitted to the logger at INFO level.

to_mantissa_exponant(iq, masks=(-16, 15))

Convert a packed mantissa/exponent IQ value into a float.

VIPIR binary sometimes encodes floating values as a packed mantissa/exponent in a single integer. This helper extracts the mantissa and exponent bits using bitmasks and reconstructs the floating value.

Parameters:

Name	Type	Description	Default
iq		float Packed IQ integer value read from the binary stream.	required
masks		tuple, optional Tuple of integer masks used to extract mantissa and exponent bits (default (-16, 15)).	(-16, 15)

Returns:

Type	Description
float	Decoded floating-point value.