Hello, my name is Russell Hoppenstein, and I'm the High Speed Data Converter Application Manager at Texas Instruments. In this RF Sampling Series, we're going to look that why RF sampling. And I'm going to give you a hint to the answer, it's going to be bandwidth. But we're going to look at a few different cases to see how it manifests itself.

Now, first, we'll look at the bandwidth considerations related to pulses. Now, if we had an ideal impulse function and we did a Fourier transform on that, that would convert it into infinite frequency. But that's not very realistic.

If we look at something a little bit more realistic, a finite pulse in time, like a boxcar function, and we translate that into the frequency domain, it translates into a sinc function. And what we see here is the pulse width T will translate to the main lobe width that is inversely proportional to T. So 1 over T.

Now, if we take the case as those pulses gets smaller, the bandwidth and the frequency domain is now getting larger. And you can see the [? extend ?] here as we get smaller and smaller, that bandwidth is going to get higher and higher. And the need for an RF sampling converter sampling at a very high speed is going to be required.

Now, looking at bandwidth considerations related to frequency, sampling theorem dictates that a minimum sampling rate must be at least 2x the desired bandwidth. Now, in practice more is generally required.

But looking at one case, where we're talking about one large signal bandwidth, and so we need a sampling converter that's capable of capturing that entire bandwidth.

But we can also look at another case in which it's not one contiguous frequency space. But it's broken up into two or more bands. And if we take both of those together, and we look at the entire system bandwidth, we can now capture both of those simultaneously.

So before we might have to have a separate receiver for each of those bands. Now we can capture both of them at the same time.

And this leads me into kind of the flexibility and the tunable nature of the RF sampling architecture. Previously, we would have a mixer within a synthesizer. We would convert that down to the baseband or IF and then capture with ADC.

But now with the RF sampling ADC, we don't need to know the exact location of our signal in the RF space. We have a bit of tunability, if you will, because we can capture it no matter where that signal is. And we don't even really need to know where it lies. We can capture the entire bandwidth and in digital signal processing, we can find out where the relevant information is and process from there.

Well, thank you for listening. If you have any further technical questions on this topic, feel free to contact our application experts at e2e.ti.com.