Transmitter parameter

AN4387

12/22

DocID025465 Rev 1

4.4

Transmitter unwanted emissions in out-of-band domain

The measurement shall be performed at the lowest and the highest channel on which the

equipment can operate.

The spectrum analyzer must be set with:

Centre Frequency: 2484 MHz; Span: 0 Hz; Resolution BW: 1 MHz

Filter mode: Channel filter; Video BW: 3 MHz; Detector Mode: RMS

Trace Mode: Clear/Write; Sweep Mode: Continuous; Sweep Points: 5000

Trigger Mode: Video trigger; Sweep Time: Suitable to capture one transmission burst

For the segment 2483.5 MHz to 2485.5 MHz:

–

Adjust the trigger level to select the transmissions with the highest power level.

–

Set a window (start and stop lines) to match with the start and end of the burst and

in which the RMS power shall be measured using the time domain power function.

–

Select RMS power to be measured within the selected window and note the result

which is the RMS power within this 1 MHz segment (2483.5 MHz to 2484.5 MHz).

–

Compare this value with the applicable limit provided by the mask.

–

Increase the center frequency in steps of 1 MHz and repeat this measurement for

every 1 MHz segment within the range 2483.5 MHz to 2485.5 MHz. The center

frequency of the last 1 MHz segment shall be set to 2485.5 MHz - 0.5 MHz (which

means this may partly overlap with the previous 1 MHz segment).

For the segment 2485.5 MHz to 2487.5 MHz:

Change the center frequency of the analyzer to 2486 MHz and perform the measurement

for the first 1 MHz segment within range 2485.5 MHz to 2487.5 MHz. Increase the center

frequency in 1 MHz steps and repeat the measurements to cover this whole range.

The center frequency of the last 1 MHz segment shall be set to 2487.5 MHz - 0.5 MHz.

For the segment 2398 MHz to 2400 MHz:

Change the center frequency of the analyzer to 2399.5 MHz and perform the measurement

for the first 1 MHz segment within range 2398 MHz to 2400 MHz.

Reduce the center frequency in 1 MHz steps and repeat the measurements to cover this

whole range.

The center frequency of the last 1 MHz segment shall be set to 2396 MHz + 0.5 MHz.

For the segment 2396 MHz to 2398 MHz:

Change the center frequency of the analyzer to 2397.5 MHz and perform the measurement

for the first 1 MHz segment within range 2396 MHz to 2398 MHz. Reduce the center

frequency in 1 MHz steps and repeat the measurements to cover this whole range.

The center frequency of the last 1 MHz segment shall be set to 2396 MHz + 0.5 MHz.

A prescan analysis in the range below 2.4 GHz (Figure 7) permits to search for unwanted

spurious: no particular emissions were found.