ISM 433/315 MHz FSK/ASK Transmitter – Data Sheet

AS3901

Rev. 6, August 2000

Page 16 of 18

Figure 8:

Modulation bandwidth of the AS3901 in AKS operation at 9.2 kbit/s, measured

close to the EN 300-220-1 recommendatio for wide-band equipment, clause 8.6.

Instead of 5 kHz video bandwidth (VBW) 10 kHz was used. The markers were set

up to the band edges. (433.050 MHz, 434.790 MHz) The recommendation says

that the spectrum should be observed at least 1 MHz from the ISM band edges,

but it was measured with larger frequency span.

Figure 9:

Spurious emissions of the AS3901 in FSK operation, measured close to the EN 300-220-

1Recommendation for wide-band equipment, clause 8.7, without modulation. (Only

difference: 100 kHz RBW was used instead of 120 kHz). From the measurement it can be

seen that the main critical spurious emission is generated by the 13.56 MHz clock frequency.

The level of CLK spurious is near –48 dBM so the suppression is 45 dB for this component.