HIGH-FREQUENCY SIGNAL PROCESSING DEVICE

摘要

A high-frequency signal processing device having a frequency synthesizer (PLL: Phase Locked Loop) is provided. A control circuit measures oscillation frequencies obtained upon setting a bias current of an oscillation circuit to first and second bias setting values and acquires a frequency difference amount of the oscillation frequencies. The frequency difference amount may be acquired as difference amount of setting values of a coarse adjustment capacitance setting signal (CTRM) using, for example, an automatic frequency selector unit. The control circuit retains a relationship of a difference amount of bias setting values and a difference value of setting values of the CTRM and approximating the relationship to a linear function. Thereafter, the control circuit defines, upon switching the bias current during locking of the PLL, the CTRM based on the linear function and switches the CTRM together with the bias current.

主权项

1. A high-frequency signal processing device comprising:
an oscillation circuit for generating an oscillation output signal having a predetermined frequency, controlling a frequency at a first resolution corresponding to a first frequency setting signal, and controlling a frequency at a second resolution that is higher than the first resolution corresponding to a second frequency setting signal, the oscillation circuit being operated with a bias current corresponding to a bias setting signal; a feedback loop circuit for controlling the second frequency setting signal by feedback control when a loop setting signal is at an ON level so that a phase of a signal obtained by feeding back the oscillation output signal and a phase of a reference locking signal are matched, and setting the feedback control to an opened state when the loop setting signal is at an OFF level; a measurement circuit for measuring a frequency of the oscillation output signal in a state in which the loop setting signal is at the OFF level; and a control circuit for controlling the bias setting signal and the first frequency setting signal, wherein the control circuit carries out:
a first processing of measuring a frequency difference amount between a frequency of the oscillation output signal obtained upon setting the bias setting signal to a first bias setting value and a frequency of the oscillation output signal obtained upon setting the bias setting signal to a second bias setting value by making the measurement circuit measure in the state in which the loop setting signal is at the OFF level;a second processing of retaining a relationship of the frequency difference amount and a variable bias amount between the second bias setting value and the first bias setting value obtained in the first processing; anda third processing of, in the state in which the loop setting signal is at the ON level, defining a changed amount of the frequency of the oscillation output signal to a changed amount of the bias setting signal upon changing the bias setting signal, and controlling the first frequency setting signal based on the defined changed amount of the frequency.