The Frequency-Split logical device splits up a frequency value in a coarse part (1 MHz resolution) and a fine part. The coarse part is set at the RF device while the fine part is set as an offset to the nominal IF frequency at a device at the IF stage. A typical application for the Frequency-Split device is to set the transmit/receive frequencies with a transceiver that only is capable to tune it's frequencies in steps of 1 MHz. The figure below shows the usage of the Frequency-Split device in an up-link application, however it may be used for down-link frequencies as well.
The Frequency-Split device processes the frequency setting messages in both directions. If you change the frequencies directly at the devices, the Frequency-Split recognizes this and updates the common frequency setting accordingly.
When setting the coarse part of the frequency, the Frequency-Split rounds to the nearest full MHz. Hence the offset applied to the IF frequency setting will be +/- 500 kHz.
Device window pages
The following table shows which device window pages are available with this individual device type. Tool-bar functions not mentioned here are described at the general description of device windows .
--- The main control page for the device. The only operational parameter shown on this page is the common frequency value.
--- The device info page.
--- The maintenance page. The configuration parameters from this page are described below.Configuration parameters
At the maintenance page of the device window there are a couple of configuration parameters which must be set to interconnect the Frequency-Split device with the devices that will perform the frequency setting.
| parameter | description |
|---|---|
| fineFreqId | Enter the message identifier here of the parameter which shall receive the fine part frequency setting, e.g. "MODEM-1.tx.frequency". Look at the list of device driver variable definitions to see correct name of this setting at the device type you are using. |
| coarseFreqId | Enter the message identifier here of the parameter which shall receive the coarse part frequency setting, e.g. "TRANSCEIVER.tx.frequency". Look at the list of device driver variable definitions to see correct name of this setting at the device type you are using. |
| nominalFreq | The nominal IF frequency to be set at the "fineFreqId" parameter must be specified here. |
Variables defined by this device driver
| name | type | flags | range |
|---|---|---|---|
| info.driver | TEXT | R/O | StringRange R/O |
| info.type | TEXT | R/O | StringRange R/O |
| info.frame | TEXT | R/O | StringRange R/O |
| config.fineFreqId | TEXT | SAVE SETUP | StringRange |
| config.coarseFreqId | TEXT | SAVE SETUP | StringRange |
| config.nominalFreq | FLOAT | SAVE SETUP | DoubleRange (0.000 .. 30000.000) |
| frequency | FLOAT | DoubleRange (0.000 .. 0.000) |