caliper

package
v0.0.0-...-be2d6f2 Latest Latest
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 Go to latest Published: May 13, 2026 License: Apache-2.0 Imports: 11 Imported by: 0

Documentation

Index

Constants

View Source 
const CoaxDelayNsPerM = 5.05

CoaxDelayNsPerM is the propagation delay of RG58 coaxial cable in ns/m

View Source 
const SpeedOfLight = 299792458.0

SpeedOfLight in meters per second

Variables

This section is empty.

Functions

func AntennaElectricalDelayNs 

func AntennaElectricalDelayNs(gen AntennaGen) (float64, error)

AntennaElectricalDelayNs returns the electrical delay in nanoseconds for a given antenna generation

func GenerateSVG 

func GenerateSVG(tor *TORFile, peaks []Peak, result *MeasurementResult, w io.Writer) error

GenerateSVG creates an SVG plot of the full OTDR trace with peaks annotated

func GenerateSVGWindow 

func GenerateSVGWindow(
	tor *TORFile, peaks []Peak, result *MeasurementResult, w io.Writer, minTimeNs, maxTimeNs float64,
) error

GenerateSVGWindow creates an SVG plot of the OTDR trace for a specific time window (minTimeNs to maxTimeNs), with peaks annotated.

func GenerateSVGZoomed 

func GenerateSVGZoomed(tor *TORFile, peaks []Peak, result *MeasurementResult, w io.Writer, maxTimeNs float64) error

GenerateSVGZoomed creates an SVG plot of the OTDR trace zoomed to the first maxTimeNs nanoseconds, with peaks annotated.

func PeakDescription 

func PeakDescription(model ReceiverModel) map[string]string

PeakDescription returns the descriptions for OA/OB/OC/OD based on receiver model

func SMAPortOffsetNs 

func SMAPortOffsetNs(model ReceiverModel) (float64, error)

SMAPortOffsetNs returns the delay in nanoseconds between the FO Out port (where OA is measured) and the SMA port (where downstream devices connect).

Types

type AntennaGen 

type AntennaGen string

AntennaGen represents antenna generation and phase 

const (
	Gen2Phase0  AntennaGen = "gen2-p0"
	Gen2Phase1  AntennaGen = "gen2-p1"
	Gen2Phase2  AntennaGen = "gen2-p2"
	Gen2aPhase2 AntennaGen = "gen2a-p2"
)

type DataPoint 

type DataPoint struct {
	DistanceM   float64
	AmplitudeDB float64
}

DataPoint is a single OTDR measurement

func (DataPoint) TimeNs 

func (d DataPoint) TimeNs(refractiveIndex float64) float64

TimeNs converts distance in meters to time in nanoseconds using the refractive index

type DelayResult 

type DelayResult struct {
	SMAPortOffsetNs          float64 `json:"sma_port_offset_ns"`
	RxDelayNs                float64 `json:"rx_delay_ns"`
	CableDelayNs             float64 `json:"cable_delay_ns"`
	AntennaOpticalDelayNs    float64 `json:"antenna_optical_delay_ns"`
	AntennaElectricalDelayNs float64 `json:"antenna_electrical_delay_ns"`
	TotalDelayNs             float64 `json:"total_delay_ns"`
	CoaxCableLengthM         float64 `json:"coax_cable_length_m"`
	CoaxCableDelayNs         float64 `json:"coax_cable_delay_ns"`
	EndToEndDelayNs          float64 `json:"end_to_end_delay_ns"`
}

DelayResult captures the computed delays between peaks

type MeasurementResult 

type MeasurementResult struct {
	DeviceName   string        `json:"device_name"`
	SerialNumber string        `json:"serial_number"`
	Model        ReceiverModel `json:"model"`
	AntennaGen   AntennaGen    `json:"antenna_gen"`
	TORFile      string        `json:"tor_file"`
	DateTime     string        `json:"date_time"`
	Settings     TORSettings   `json:"settings"`
	Peaks        []PeakResult  `json:"peaks"`
	Delays       DelayResult   `json:"delays"`
	Trace        []TracePoint  `json:"trace"`
}

MeasurementResult is the detailed per-device JSON output

func ComputeResult 

func ComputeResult(
	tor *TORFile,
	peaks []Peak,
	name, serial string,
	model ReceiverModel,
	antennaGen AntennaGen,
	coaxCableLengthM, launchCableLengthM float64,
) (*MeasurementResult, error)

ComputeResult computes the full measurement result from parsed TOR data and peaks.

type Peak 

type Peak struct {
	Label       string  // OA, OB, OC, OD
	DistanceM   float64 // distance in meters at peak maximum
	AmplitudeDB float64 // amplitude in dB at peak maximum
	TimeNs      float64 // time in nanoseconds
	Index       int     // index into DataPoints
}

Peak represents a detected reflective event in the OTDR trace

func DetectPeaks 

func DetectPeaks(tor *TORFile, launchCableLengthM float64) ([]Peak, error)

DetectPeaks finds the 4 reflective peaks (OA, OB, OC, OD) in the OTDR trace.

OA is found via local prominence detection (it is a strong reflection from the FO Out connector). OB, OC, OD are found by searching for the highest-amplitude raw data point inside fixed time windows, because the connectors at OB and OC can produce subtle reflections (e.g. Q-ODC-12 and FC APC) that don't exceed the prominence threshold.

OD is anchored to the strongest reflection past OB (the antenna optical isolator), and OC is then located in a small window before OD. This avoids any reliance on cable-end detection and prevents post-OD saturation noise from being mistaken for a peak.

launchCableLengthM specifies the length of the launch cable in meters. Any peaks within this distance from the start of the trace are ignored, as they are reflections from the launch cable connectors rather than the system under test. Use 0 if no launch cable is present.

type PeakGroup 

type PeakGroup struct {
	StartIdx   int
	EndIdx     int
	PeakIdx    int
	PeakDistM  float64
	PeakAmpDB  float64
	Prominence float64
}

PeakGroup is a cluster of consecutive elevated data points forming a single reflection event

type PeakResult 

type PeakResult struct {
	Label       string  `json:"label"`
	Description string  `json:"description"`
	DistanceM   float64 `json:"distance_m"`
	AmplitudeDB float64 `json:"amplitude_db"`
	TimeNs      float64 `json:"time_ns"`
}

PeakResult captures a single detected peak

type ReceiverModel 

type ReceiverModel string

ReceiverModel represents the Huber-Suhner GNSS receiver model 

const (
	GNSSoF16RxE   ReceiverModel = "GNSSoF16-RxE"
	GNSSPoF164RxE ReceiverModel = "GNSSPoF16-4RxE"
)

type TORFile 

type TORFile struct {
	DateTime               time.Time
	InstrumentInfo         string
	ModuleSerialNumber     string
	CableID                string
	FiberID                string
	FiberType              int
	Wavelength             int
	PulseWidth             int
	RefractiveIndex        float64
	DistanceUnit           int
	Average                int
	End                    float64
	Start                  float64
	Resolution             float64
	DistanceRange          int
	LossThreshold          float64
	ReflectanceThreshold   float64
	EndOfFiberThreshold    float64
	BackscatterCoefficient float64
	HighResolution         int
	DataPoints             []DataPoint
}

TORFile represents a parsed Luciol LOR-220 OTDR .tor file

func ParseTOR 

func ParseTOR(path string) (*TORFile, error)

ParseTOR parses a Luciol OTDR .tor text file from a path

func ParseTORReader 

func ParseTORReader(r io.Reader) (*TORFile, error)

ParseTORReader parses a Luciol OTDR .tor text file from a reader

type TORSettings 

type TORSettings struct {
	Wavelength             int     `json:"wavelength_nm"`
	PulseWidth             int     `json:"pulse_width"`
	RefractiveIndex        float64 `json:"refractive_index"`
	Resolution             float64 `json:"resolution_m"`
	Start                  float64 `json:"start_m"`
	End                    float64 `json:"end_m"`
	BackscatterCoefficient float64 `json:"backscatter_coefficient"`
	Average                int     `json:"average"`
	LaunchCableLengthM     float64 `json:"launch_cable_length_m"`
}

TORSettings captures the relevant OTDR measurement settings

type TracePoint 

type TracePoint struct {
	TimeNs      float64 `json:"time_ns"`
	AmplitudeDB float64 `json:"amplitude_db"`
}

TracePoint is a single data point in the OTDR trace for the report

Source Files

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