If we were to create a waveform strictly from the numerical data in the table it might look something like the oscilloscope image to the right. A table of measures is included that indicates how these discrete samples of waveform amplitude can be numerically represented, sampling over time left-to-right across the waveform. In the figure below each blue dot represents a point in time of a discrete sample of amplitude. We could set our oscilloscope to measure the wave’s amplitude in discrete steps across the waveform, perhaps 10 separate instantaneous measurements per wavelength over equal intervals of time. What if we want to represent the waveform with numbers, and specifically, with a limited set of numbers instead of a huge laundry list of values? The oscilloscope is providing us an image of the continuous analog wave – by definition, a continuous or unbroken measurement of the wave, and particularly of its amplitude.īut a continuous measurement is difficult to record or represent beyond that nice flowing waveform image. To the left side of the screen is a scale by which we can measure the amplitude at any position on the waveform. Imagine we are measuring this signal, perhaps with a nice oscilloscope that will show us this waveform on its screen.

We depict such signals (and their electromagnetic counterparts that are radiated from our antennas) with sine wave forms like that shown to the left, where the amplitude (height) of the wave from the center propagation axis is the instantaneous voltage of the signal as it pulses back and forth. We refer to the polarized voltages as positive and negative voltage. That is, the electrons flow back and forth in the circuit at radio frequencies as the voltage reverses polarization, providing electric potential first in one direction and then reversing to the opposite direction.

Just what is a digital signal? Keeping it practical and related to ham radio, let’s consider the digitization of an RF waveform… from the git go!Īn RF signal in an electric circuit is an alternating current (AC) signal. What is it all about? What does it do for my station?īefore we consider some of the very cool things that DSP can do in our transceiver, let’s make sure we have a little understanding of the whole “digital” thing. Operators tend to love the convenience of it…īut very few beginner amateurs have a basic understanding of it!ĭigital Signal Processing, or DSP.

Ham radio digital mode samples