BACKGROUND

The present invention generally relates to transmitter architectures, and, more particularly, to efficient multi-band transmitters.

Low-power sensor arrays are increasingly used for a variety of applications, including internet of things (IoT) devices, implantable devices, wearable devices, energy harvesting systems, seismic sensors, structural health monitoring systems, and multi-channel/multi-mode devices. Such transmitters may need to transmit on a variety of different frequency bands, in accordance with the demands of a particular application.

SUMMARY

A transmitter includes a frequency adjuster coupled to a ring oscillator to reduce latency and power consumption and to receive a signal from the ring oscillator. The frequency adjuster includes logic circuits to adjust the signal to a selected transmission frequency band. A band switch is coupled to the ring oscillator and the frequency adjuster to select logic circuits within the frequency adjuster to determine the selected transmission frequency band from a set of output frequency bands. A first radio front end is coupled to the frequency adjuster to transmit the signal on the selected transmission frequency band.

A sensor system includes a sensor that generates measurement data, a ring oscillator-based transmitter, and an antenna that receives a transmitted modulated signal. The ring oscillator-based transmitter includes a frequency adjuster, a band switch, and a first radio front end. The frequency adjuster is coupled to a ring oscillator to reduce latency and power consumption and to receive a signal from the ring oscillator. The frequency adjuster including logic circuits to adjust the signal to a selected transmission frequency band. The band switch is coupled to the ring oscillator and the frequency adjuster to select logic circuits within the frequency adjuster to determine the selected transmission frequency band from a set of output frequency bands. The first radio front end is coupled to the frequency adjuster to modulate the measurement data onto the signal and to transmit the signal on the selected transmission frequency band.

A method for transmitting a signal includes tuning a ring oscillator output to a base frequency to reduce latency and power consumption. The ring oscillator output is switched to a selected transmission band using a frequency adjuster. The ring oscillator output is adjusted to a second frequency on the selected transmission band using multiple phase outputs of the ring oscillator. The adjusted signal is transmitted at the selected transmission band.

These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.

