Note: In earlier versions of the 802.11 standard, the (BCC) OFDM example was given in Annex G. However, an error existed (e.g. in IEEE Std 802.11-2007) in that the FCS was incorrect (see link or search online for "IEEE 802.11-09/0042r0").
The WiFi (802.11) standards documents are free to download from the IEEE webpages (see, for example, here). (Sadly, you are required to register first, which I would describe as irritating and pointless).
In Part I of this blog, we saw that we can construct two partially correlated signals, x_{1}(t) and x_{2}(t), as:
Note: This blog is split into two parts because edaboard limits the number of pictures and equations per blog. The second part can be found here: [link].
Introduction
It is often useful to be able to generate (real or complex-valued) signals with specific cross-correlations. In the simplest case, this means we want to produce two signals with a specified cross-correlation (and specified powers). Or, in the general case, it means we want to specify an
I was recently asked how to estimate the frequency of a noisy sine wave over a short capture. In this context, 'short' means the total capture duration relative to the period of the sine wave. So we may have, at most, a few periods of the sine wave (or, at worst, less than one period). Here is an example (download raw data: sine_data_40k.zip):
Clealy, there is less than
We often plot some data on a graph and wonder if there might be a simple mathematical function to describe what we see:
In many cases, a polynomial approximation would be particularly useful. That is, we want to describe the line in the form: