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"Advanced Span, up to 100KHz with 300Hz RBW"
October 2009

It is quite difficult to express in writing just how advanced the functionality that shall be discussed in this post is. We could say, without fear of being excessively exaggerated, that there is no other feature that better defines the difference between the H45 Advance and the rest of the field spectrum analysers for the measurement of radio-television signals in the market today.

Until now, when the installer needed to focus the analysis of the spectrum onto a single channel, he was faced with a bandwidth limit between 5 and 8 MHz, depending on the brand and model of the meter being used. This span configuration could be enough to visualise the shape of an analogue or digital channel, but it lacked the detail and depth if a more precise technical study was required in the set channel frequency.

span cofdm 8 mhz
Fig.1 - Traditional Span, COFDM channel at 10MHz

span 5 mhz
Fig.2 - same fig.1 channel with span at 5Mhz

Even if we reduced the span configuration at its maximum of 5MHz, as in figure 2 above, we were able to identify some additional incidences, such as ripple effects for example, but not much more. In essence, with this technical obstacle, we were limited to analysing out-of-band incidences, losing the important spectrum sight of what could be happening inside the channel.

In the next figure we can observe the detailed spectrum analysis only available because of the development of Digital Processing in the H45 Field Spectrum Analyser. We have taken the same channel analysed in figures 1 and 2 above and have zoomed into the channel up to 50 and 80 times greater than in any other portable meter in the market today. It is an in-band zoom of 100KHz of bandwith, with 300Hz of resolution. Simply outstanding.

d`sm 100 khz rbw 300 hz
Fig. 3 – same channel as fig.1 & 2 with 100KHz span and 300Hz RBW

Say, for example, that you have incidences with the RDS carrier in-band. Would you be able to isolate and troubleshoot it with the resolution filters and span bandwidths of traditional meters? What if you needed to analyse the interference of a Tetra signal? What if you needed to visualise a narrow FM signal?

This type of analytical study stayed out of our range in the field when we wanted to study the radioelectric spectrum, remaining the exclusivity of expensive laboratory equipment.

Here are some expamples of signals that can coexist and interfere in our day-to-day SMATV installations and that we shall be able to detect and troubleshoot now with our H45 Advance meter and its advanced span configuration:

1. Example of a narrow FM signal used by radio amateurs world-wide.

span 100 khz rbw 60 hz
Span de 100KHz, RBW 60Hz

2. Example of a Tetra signal. A protocol standard used by closed-group digital radio communications, used primarily by public organisations such as police forces, fire-fighters...

span 100 khz rbw 60 hz
Span de 100 Khz, RBW 60Hz

3. FM with RDS: Conventional FM signal. Using a combination of a narrow span and the max/min marks feature, we can observe the RDS carrier of such signal.

span 500 khz rbw 900 hz
Span de 500KHz, RBW 900Hz

4. DVB-T signal: Example of the detailed analysis of a COFDM multiplex, where we can observe the last carrier.

span 100 khz rbw 300 hz
Span de 100KHz, RBW 300Hz


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