An agricultural row unit includes a hydraulic cylinder coupled to a support member for urging a soil-engaging tool coupled to the support member downwardly toward the soil. The device includes a drive unit, a measurement unit and a determination unit. The loop filter outputs a predetermined voltage in response to an output signal from said phase detector. The cavity is formed from the upper surface of the substrate downward to the bottom so that the LED chips are wholly inlaid in the cavity. In general, the modulator has three modes of operation: an Enhanced Data Rates for Global System for Mobile Communications Evolution mode, which may be referred to as an 8-Level Phase Shift Keying mode; a Gaussian Minimum Shift Keying mode; and a Wideband Code Division Multiple Access mode. The method includes: performing pitch detection on an input signal in a signal domain, and obtaining a candidate pitch; performing linear prediction on the input signal, and obtaining an LP residual signal; setting a candidate pitch range that includes the candidate pitch; searching the candidate pitch range for the LP residual signal, and obtaining a selected pitch.