Various methods provide for trimming the gain in a dual-port phase-locked loop (PLL) of a radio transceiver. Use is made of the radio's demodulator to perform modulation accuracy measurements, thereby reducing the cost and complexity of external test equipment.

Example radio frequency (RF) transmitters and associated methods are disclosed. One example RF transmitter includes an RF oscillator, a real-time clock (RTC) oscillator. and a control circuit. The control circuit is configured to determine whether a calibration of the RF oscillator is needed; electrically couple the RF oscillator to the RTC oscillator and initiate calibrating of the RF oscillator using the RTC oscillator when it is determined that the calibration is needed; and activate the RF oscillator to operate in an open-loop mode to generate an RF signal for data transmission. The calibration can be performed in a closed-loop mode before the data transmission or in an open-loop mode during the data transmission.

Systems and methods disclosed herein include a correction circuit. The correction circuit may include signal conditioning circuitry that is configured to condition a received reference signal. The correction circuit may include a filter that is configured to filter the conditioned signal received from the signal conditioning circuitry. The correction circuit may include phase detector circuitry that is configured to generate at least one output signal based on measuring a phase shift between a received plurality of input signals. At least one of the plurality of input signals may include the conditioned signal received from the filter.

Various methods provide for trimming the gain in a dual-port phase-locked loop (PLL) of a radio transceiver. Use is made of the radio's demodulator to perform modulation accuracy measurements, thereby reducing the cost and complexity of external test equipment.

Various methods provide for trimming the gain in a dual-port phase-locked loop (PLL) of a radio transceiver. Use is made of the radio's demodulator to perform modulation accuracy measurements, thereby reducing the cost and complexity of external test equipment.

Embodiments described herein include a quadrature phase corrector (QPC) which includes multiple differential amplifies for correcting the phase of one or more clock signals. In one embodiment, the differential amplifiers are arranged in an input stage, cross-coupled stage, and ring stage. The input stage receives and buffers the input clock signal (or signals). The cross-coupled stage includes one or more latches that force one clock signal high and another low which causes the QPC to oscillate. The ring stage outputs four clock signals with adjusted phases relative to the input clock signals. In one example, the ring stage outputs a quadrature clock signal that includes four clock signals phase shifted by 90 degrees.

A protocol to be used in the transmission is determined. Based upon the protocol, the transmission frequency range of a clock is selectively altered. TPMS data is transmitted according to the altered transmission frequency range of the clock.

Various methods provide for trimming the gain in a dual-port phase-locked loop (PLL) of a radio transceiver. Use is made of the radio's demodulator to perform modulation accuracy measurements, thereby reducing the cost and complexity of external test equipment.

The present electronic generator of modulated subcarrier pulse signals includes a module (15) for modulating a pulse train, the position and amplitude of which are controllable, forming a switching signal (S.sub.3); a switching module (16), connected to the output of the module (15) for modulating a pulse train, including at least one transistor (22), controlled by said switching signal (S.sub.3), a voltage-controlled frequency-locking oscillator (18) having a frequency-locking band around a free oscillation frequency controlled by a control voltage, connected to the output of the switching module (16), the switching module making possible the injection of a periodic pulse signal (S.sub.4) having a frequency spectrum including at least one frequency line within said frequency locking band. Such arrangement makes it possible to obtain, at the output of the oscillator, frequency-controlled, phase-controlled and amplitude-controlled modulated subcarrier pulsed signals (S.sub.5).

Various methods provide for trimming the gain in a dual-port phase-locked loop (PLL) of a radio transceiver. Use is made of the radio's demodulator to perform modulation accuracy measurements, thereby reducing the cost and complexity of external test equipment.