Method for obtaining field strength information

摘要

A method includes generating an input voltage for an operational amplifier from a received electromagnetic signal in a receiver unit by an input resistance and generating an output voltage by the operational amplifier by a fixed amplification factor. The input voltage is changed until the output voltage lies within a predefined interval that includes the value of the reference voltage. The input voltage is tapped at a divider node of a voltage divider. The gate voltage of the MOS transistor, operating within a nonlinear range and connected to the divider node, is changed to adjust the output voltage to the reference voltage such that a forward resistance of the transistor is changed nonlinearly. A field strength value received by the receiver unit is determined from a comparison of the value of the present gate voltage with quantities assigned to stored gate voltage values.

主权项

1. A method for obtaining field strength information, comprising:
storing, in a memory, an association between field strength values and predefined gate voltages; applying, by an input resistance element, a resistance value to an input signal to generate an input voltage; amplifying the input voltage by an operational amplifier to generate an output voltage; determining, by a control element, that the output voltage is outside a voltage interval associated with a reference voltage; in response to determining that the output voltage is outside the voltage interval, changing a gate voltage applied to the input resistance element to adjust the resistance value applied to the input signal in a non-linear manner to result in an adjusted output voltage by the operational amplifier; and in response to determining that the adjusted output voltage is within the voltage interval, determining, from a table, a field strength of the input signal based on the gate value applied to the input resistance element and a stored association between the field strength values and the predefined gate voltages.