Stmicroelectronics S.r.l.

Alessandro Castorina

Giuseppe Palmisano

Nunzio Spina

Giovanni Girlando

Carla Motta

A method for calibrating the DC operating point of a PWM receiver circuit is disclosed. The PWM receiving circuit includes an envelope detector having a first resistor string, and includes a bias circuit having a second resistor string and a plurality of switches. The second resistor string is coupled between a supply voltage and a reference voltage and functions as a voltage divider. Each switch, when closed, accesses a second voltage at a node of the second resistor string connected to the closed switch. To perform the calibration process, the plurality of switches is closed one at a time, and the second voltage is compared with a first voltage at a first node of the first resistor string. The switch that, when closed, produces the smallest difference between the first voltage and the second voltage remains closed after the calibration process, and is used for demodulating the PWM signal.

Digital self-calibration for automatic offset cancellation

A method for calibrating the DC operating point of a PWM receiver circuit is disclosed. The PWM receiving circuit includes an envelop detector having a first resistor string, and includes a bias circuit having a second resistor string and a plurality of switches. The second resistor string is coupled between a supply voltage and a reference voltage and functions as a voltage divider. Each switch, when closed, accesses a second voltage at a node of the second resistor string connected to the closed switch. To perform the calibration process, the plurality of switches is closed one at a time, and the second voltage is compared with a first voltage at a first node of the first resistor string. The switch that, when closed, produces the smallest difference between the first voltage and the second voltage remains closed after the calibration process, and is used for demodulating the PWM signal.

An arrangement is for measuring characteristic parameters of intermodulation distortion of a device under test. The arrangement may include a generator of at least two tones at different test frequencies, and an attenuation path feeding the device with a replica of the two tones attenuated of a factor equal to the gain of the device. The arrangement may also include a circuit for generating a difference signal between the signal output by the device and the two tones, and a circuit input with the difference signal and measuring the characteristic parameters as a function thereof.

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Aci Catena, Italy

Alessandro Castorina