Micrel, Incorporated

Joseph S Elder

Joseph T Yestrebsky

Mohammed D Islam

A single chip superhetrodyne AM receiver is disclosed herein. To compensate for process variations in the implementation of the IC, bias currents setting the operating conditions for various amplifiers and other components in the system are adjusted based on frequency control signals in a PLL circuit in the local oscillator. Since the magnitude of the control signal reflects the process variations, the bias currents are adjusted based on the control signal to offset these variations in other portions of the receiver. To further improve the signal to noise ratio of the receiver, the IF filter is tuned within a range so as not to include any integer multiple or integer divisor of the timing reference frequency. Various techniques are described for enabling a complete superhetrodyne AM receiver to be implemented on a single chip which receives an antenna input signal and outputs a digital data signal.

Method of operating radio receiver implemented in a single CMOS integrated circuit

A single chip receiver is disclosed herein. The chip only requires an external antenna for operation. A decoder is formed on chip for performing logical operations on demodulated digital data. A baseband filter is controlled by external control signals to have one of a plurality of discrete frequency response bandwidths depending on the type of signal to be received. To compensate for process variations in the implementation of the IC, bias currents setting the operating conditions for various amplifiers and other components in the system are adjusted based on frequency control signals in a PLL circuit in the local oscillator. Since the magnitude of the control signal reflects the process variations, the bias currents are adjusted based on the control signal to offset these variations in other portions of the receiver. To further improve the signal to noise ratio of the receiver, the IF filter is tuned within a range so as not to include any integer multiple or integer divisor of the timing reference frequency. Various techniques are described for enabling a complete receiver to be implemented on a single chip which receives an antenna input signal and outputs a digital data signal.

Single chip radio receiver with decoder and controllable baseband filter

A monolithic AM transmitter is disclosed. An external antenna forms part of a resonance network so that the antenna resonance point is automatically tuned to the transmit frequency. This provides flexibility with no added cost to the transmitter.

Fully integrated ALL- CMOS AM transmitter with automatic antenna tuning

A monolithic AM transmitter is disclosed. An external antenna forms part of a resonance network so that the antenna resonance point is automatically tuned to the transmit frequency. This provides flexibility with no added cost to the transmitter. Additionally, components of the transmitter can be formed on a single monolithic integrated circuit.

Fully integrated All-CMOS AM transmitter with automatic antenna tuning

Fully integrated all-CMOS AM transmitter with automatic antenna tuning

Radio receiver in CMOS integrated circuit

Fully integrated ALL-CMOS AM transmitter with automatic antenna tuning

A single chip superheterodyne AM receiver is disclosed herein. The receiver has a control pin for application of control signals to adjust a frequency response of a baseband filter to tailor its frequency response to a particular type of signal received by the receiver. Various techniques are described for enabling a complete superheterodyne AM receiver to be implemented on a single chip which receives an antenna input signal and outputs a digital data signal.

Tunable filter in radio receiver

A superhetrodyne AM receiver and digital decoder are formed on the same chip. The frequency responses of the various filters are tied to the reference frequency. To compensate for process variations in the implementation of the IC, bias currents setting the operating conditions for various amplifiers, filters, and other components in the system are adjusted based on frequency control signal in a PLL circuit in the local oscillator. Since the magnitude of the control signal reflects the process variations, the bias currents are adjusted based on the control signal to offset these variations in other portions of the receiver. To further improve the signal to noise ratio of the receiver. The IF filter is tuned within a range so as not to include any integer multiple or integer divisor of the timing reference frequency. Various techniques are described for enabling a complete superhetrodyne AM receiver to be implemented on a single chip which receives an antenna input signal and outputs a digital data signal.

Fully integrated all-CMOS AM receiver

Bias signal generator in radio receiver

A single chip superhetrodyne AM receiver including a local oscillator which sweeps through a frequency range at a rate higher than a modulation frequency of the incoming RF signal. The local oscillator frequency is mixed with the incoming RF signal. An IF filter passes a selected frequency band from the mixer to a demodulator. The demodulator is tuned to demodulate any signal within a band of frequencies determined by the sweeping of the local oscillator. This increases the signal to noise ratio of the receiver since it allows for variations in the transmitter output frequency. The frequency responses of the various filters are tied to the reference frequency and allows the user to set the tuning and alignment of the receiver. To compensate for process variations in the implementation of the IC, bias currents setting the operating conditions for various amplifiers and other components in the system are adjusted based on frequency control signals in a PLL circuit in the local oscillator.

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Orlando, FL, United States of America

Joseph S Elder