According to one embodiment, a transceiver includes: a radio transmitter including a power amplifier; a detector circuit including: a squaring circuit configured to receive an output of the power amplifier of the radio transmitter and configured to produce an output current; and a DC current absorber electrically connected to an output terminal of the squaring circuit.

According to one embodiment, a transceiver includes: a radio transmitter including a power amplifier; a detector circuit including: a squaring circuit configured to receive an output of the power amplifier of the radio transmitter and configured to produce an output current; and a DC current absorber electrically connected to an output terminal of the squaring circuit.

The present disclosure relates in general to devices, systems and methods for wireless communication, and in particular to communication using a proximity integrated circuit card (PICC). Example embodiments include a circuit (100) for a PICC, the circuit comprising an input stage (101), a decoding module (106) and a bias adjustment module (117), the bias adjustment module (117) configured to receive an output code from the decoding module and provide a bias adjustment signal to the input stage (101), the bias adjustment module (117) configured to iteratively tune the bias adjustment signal based on a measurement of the output code, with successive steps tuning the bias adjustment signal by a smaller amount until the output code is within a decoding range.

The present disclosure relates in general to devices, systems and methods for wireless communication, and in particular to communication using a proximity integrated circuit card (PICC). Example embodiments include a circuit (100) for a PICC, the circuit comprising an input stage (101), a decoding module (106) and a bias adjustment module (117), the bias adjustment module (117) configured to receive an output code from the decoding module and provide a bias adjustment signal to the input stage (101), the bias adjustment module (117) configured to iteratively tune the bias adjustment signal based on a measurement of the output code, with successive steps tuning the bias adjustment signal by a smaller amount until the output code is within a decoding range.

According to one embodiment, a transceiver includes: a radio transmitter including a power amplifier; a detector circuit including: a squaring circuit configured to receive an output of the power amplifier of the radio transmitter and configured to produce an output current; and a DC current absorber electrically connected to an output terminal of the squaring circuit.

In one example, a circuit includes a first node to receive an analog signal that is an amplitude modulated radio-frequency signal for a digital signal. An output node is configured to provide an output signal indicative of rising and falling edges of an envelope of the analog signal. The rising and falling edges are indicative of rising and falling edges of the digital signal. A first current path is disposed between a power supply node and the first node. The first current path includes a first transistor coupled between the first node and a first bias source. The first bias source is coupled between the first transistor and the power supply node. The output node is coupled to a first intermediate node in the first current path between the transistor and the first bias source. A control terminal of the first transistor is coupled to the output node via a feedback network.

In one example, a circuit includes a first node to receive an analog signal that is an amplitude modulated radio-frequency signal for a digital signal. An output node is configured to provide an output signal indicative of rising and falling edges of an envelope of the analog signal. The rising and falling edges are indicative of rising and falling edges of the digital signal. A first current path is disposed between a power supply node and the first node. The first current path includes a first transistor coupled between the first node and a first bias source. The first bias source is coupled between the first transistor and the power supply node. The output node is coupled to a first intermediate node in the first current path between the transistor and the first bias source. A control terminal of the first transistor is coupled to the output node via a feedback network.

A detector circuit includes: a squaring circuit configured to receive an output of a power amplifier of a radio transmitter and to produce an output current, the output of the power amplifier including: a desired tone; a local oscillator leakage tone; and an image tone, and the output current of the squaring circuit including: a direct current (DC) component including a function of the desired tone and an alternating current (AC) component; and a DC current absorber electrically connected to an output terminal of the squaring circuit, the DC current absorber being configured to filter out the DC component of the output current of the squaring circuit to produce a filtered output of the squaring circuit, the filtered output including the AC component including functions of the local oscillator leakage tone and the image tone.

A detector circuit includes: a squaring circuit configured to receive an output of a power amplifier of a radio transmitter and to produce an output current, the output of the power amplifier including: a desired tone; a local oscillator leakage tone; and an image tone, and the output current of the squaring circuit including: a direct current (DC) component including a function of the desired tone and an alternating current (AC) component; and a DC current absorber electrically connected to an output terminal of the squaring circuit, the DC current absorber being configured to filter out the DC component of the output current of the squaring circuit to produce a filtered output of the squaring circuit, the filtered output including the AC component including functions of the local oscillator leakage tone and the image tone.

In accordance with an embodiment, an envelope detector includes a first transistor having a first current conduction terminal coupled to a first connection node; a second current conduction terminal coupled to an intermediate node; and a control terminal coupled the signal input node and to a biasing node; a second transistor having a first current conduction terminal coupled to the intermediate node; a second current conduction terminal coupled to a second connection node; and a control terminal coupled to the biasing node; and a first temperature compensating transistor that is diode-connected and coupled between a compensation output node and the biasing node. The second connection node is coupled to the compensation output node and the first connection node is coupled to a detector output.