Data AcQuisition And Real-Time Analysis
Scope - Spectrum - Spectrogram - Signal Generator
Software for Windows
Science with your Sound Card!
The following is from the Daqarta Help system:



Spectrum Analyzer

Signal Generator

(Absolutely FREE!)


Pitch Tracker


DaqMusiq Generator
(Free Music... Forever!)

Engine Simulator

LCR Meter

Remote Operation

DC Measurements

True RMS Voltmeter

Sound Level Meter

Frequency Counter
    Spectral Event

    MHz Frequencies

Data Logger

Waveform Averager


Post-Stimulus Time
Histogram (PSTH)

THD Meter

IMD Meter

Precision Phase Meter

Pulse Meter

Macro System

Multi-Trace Arrays

Trigger Controls


Spectral Peak Track

Spectrum Limit Testing

Direct-to-Disk Recording



Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Auditory phenomena

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery


Product test

Contact us about
your application!

Sine Wave Phase

Phase is the measure of the starting point of one sinusoid relative to another. In the sine wave clock example the reference starting point was the 9 o'clock position, so any wave that starts there is "in phase" with the reference wave. If a wave starts anywhere else, its angle relative to this reference is its "phase angle". A wave that starts at 6 o'clock (cosine) is thus at an angle of 90 degrees relative to the reference sine. The cosine (open dots) reaches 12 o'clock just as the sine (solid dots) hits 9 o'clock to start a new cycle:

In mathematics the 3 o'clock position is always used as the starting point, and everything runs counter-clockwise. Apart from a sign change, the results are the same.

If two identical sinusoids are added together, the result is a sinusoid with twice the amplitude. If the two waves are shifted so that they are 180 degrees out of phase, then the positive portions of one wave will cancel the negative portions of the other and the sum will be zero. At intermediate phase angles, the sum can vary over the range from 0 to 200%. At 120 or 240 degrees, the sum will be the same magnitude as either of the original values, but at an intermediate phase.

See also Sine Wave Basics, Magnitude via Vector Sum, Making Waves via Sine Wave Synthesis


Questions? Comments? Contact us!

We respond to ALL inquiries, typically within 24 hrs.
Over 35 Years of Innovative Instrumentation
© Copyright 2007 - 2023 by Interstellar Research
All rights reserved