Thursday, January 27, 2011

Voltage divider calculator for Radiometrix NTX2

In the configuration being used to drive the Radiometrix NTX2 in GAGA-1 there are two resistors (called them R1 and R2) that are creating a voltage divider and a third resistance (the input impedance of the module).

The module takes 0-3V on the TX pin and converts it to a 0-5Khz frequency shift from the centre frequency.

So to make calculations easy I made a little spreadsheet that allows you to punch in the two resistor values, the voltage supplied to the voltage divider and the input impedance to get a predicated pair of voltages sent to the TX pin, plus the corresponding frequency shift.

It's an Apple Numbers file and you can get it here (Excel version).

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