Elenco PK101 w/ Computer Interface - Manual (Page 5)

And this
waveform might look
like this.
Contact Elenco Electronics if you have any questions about this.
Limitations of Winscope and its interface:
By using the microphone audio input and the flexible processing power of the personal computer,
we have created an inexpensive and easy-to-use way of looking at electronic signals. However, no
electronic oscilloscope or spectrum analyzer ever made works on all electronic signals, and simi-
larly Winscope has limitations. The projects in this booklet were written to minimize those limita-
tions.
Winscope can only measure changing signals (AC voltages, >20 Hz frequency) and cannot meas-
ure fixed voltages (DC voltages, such as a battery), due to the design of the microphone input.
Fixed voltages are not very exciting to look at anyway. Slow-changing or transient signals (such as
when you first turn on power to a circuit) will be displayed in a distorted form.
Winscope works best on signals up to about 5 KHz, since its sampling rate is limited to 44 KHz. If
you attempt to measure signals that are higher than this then you will get wrong results due to
undersampling. This is a narrow range but it covers human voice and most (but not all) music. AM
and FM radio frequencies cannot be measured. Every measurement you make will have some
amount of random “chatter” superimposed on the signal of interest. This chatter is due to the limit-
ed sampling rate and from the PC-interface cable picking up energy from other electronic instru-
ments in the vicinity (including room lights and your computer), hence it cannot be avoided.
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