Channelization, or channel spacing, is the frequency difference between two adjacent frequency allocations in a frequency plan. For example, in GSM applications, the channel spacing is typically 200kHz.The Local Oscillator (LO) on the board can be configured so that the frequency step is equals to the channel spacing when moving the feedback divider from one division ratio to the next. The high resolution Modulus on the 8V97051 also allows to use the same input reference frequency to achieve different channelization requirements. Using a unique PFD frequency for several needed channelization requirements allows the user to design a loop filter for the different needed setups and ensure the stability of the loop.
The channel spacing is given by fPFD/MOD, where fPFD is the Phase an Frequency Detector (PFD) frequency, and MOD is the feedback divider Modulus.
The Timing Commander GUI can determine the different settings based on the required channel spacing that the user wants. Or the user can provide the INT, FRAC and MOD of the feedback divider ratio and the GUI will calculate the channel spacing. The tool will also calculate the locations of the integer boundary spurs when applicable. It will also calculate the loop bandwidth, and the phase margin so that the user can ensure the loop is stable.
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