Currently, F-Intermod assumes that the entered transmitter frequencies are unmodulated, and hence they have bandwidth only at the frequency specified in the transmitter field. However, in cases where wideband transmitter modulation is deployed, users may need to calculate intermodulation products that account for the wider bandwidth of the transmitters. This is because the broader modulation can cause intermodulation interference within the receiver’s bandwidth, particularly for strong intermodulation signals. The following procedure outlines how to input transmitters with modulated frequencies.
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Determine transmitter modulation bandwidth (
BWTx). -
Setup F-Intermod to calculate intermods only for a single intermod order (
IMOrder).
– Select the Single Intermod Order option, then
– Enter or select the desired intermod order.
Note: Separate calculations must be completed for each desired intermod order.
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Enter all channels into F-Intermod as normal. For wideband modulated transmitter channels:
– Multiply the transmitter modulated bandwidth by the intermod order.
– Add it to the receiver bandwidth (BWRx) for that channel.
– Divide by two to get the F-Intermod half bandwidth (BWHalf) and enter it into the Half Bandwidth field.
Formula:
BWHalf = ( IMOrder x BWTx + BWRx ) / 2 - Run F-Intermod to calculate the intermods for the single intermod order.
- Repeat this process for all desired intermod orders.
F-Intermod Half Bandwidth Calculator
Result
BWHalf (MHz) =
