US 12,700,928 B2 · Radio transmitter

Abstract

In an embodiment, a frequency synthesizer includes a digitally controlled oscillator configured to generate an output clock signal based on a digital control word, a clock divider configured to divide the output clock signal to generate a divided clock signal, a digital-to-time converter configured to generate a feedback clock signal based on the divided clock signal, a time-to-digital converter configured to generate a phase error signal based on a bias control word and a phase difference between a reference clock signal and the feedback clock signal, a loop filter connected to the time-to-digital converter and configured to generate the digital control word based on the phase error signal, and a calibration unit configured to generate a training sequence to generate a gain error signal, and modify the bias control word based on the gain error signal to generate a modified bias control word.

Claims20

Dependent claims

A method, comprising:

controlling a digitally controlled oscillator to generate an output clock signal;
dividing the output clock signal to generate a first divided clock signal;
generating, in a digital-to-time converter, a first feedback clock signal based on the divided clock signal;
generating, in a time-to-digital converter, a first phase error signal based on a first bias control word and a first phase difference between a reference clock signal and the first feedback clock signal;
performing a calibration process utilizing a training sequence to generate a gain error signal;
modifying the first bias control word based on the gain error signal to generate a modified first bias control word;
and
generating, in the time-to-digital converter, a second phase error signal for a second phase difference between the reference clock signal and a second feedback clock signal based on the modified first bias control word.

5 more elements

A frequency synthesizer, comprising:

a digitally controlled oscillator configured to generate an output clock signal based on a digital control word;
a clock divider configured to divide the output clock signal to generate a divided clock signal;
a digital-to-time converter configured to generate a feedback clock signal based on the divided clock signal;
a time-to-digital converter configured to generate a phase error signal based on a bias control word and a phase difference between a reference clock signal and the feedback clock signal;
a loop filter connected to the time-to-digital converter and configured to generate the digital control word based on the phase error signal;
and
a calibration unit configured to:
generate a training sequence;
generate a gain error signal by utilizing the training sequence;
and
modify the bias control word based on the gain error signal to generate a modified bias control word.

8 more elements

A radio, comprising:

an antenna port;
a transmit-receive switch connected to the antenna port;
a receive path connected to the transmit-receive switch;
a transmit path connected to the transmit-receive switch;
and
a processor configured to connect the receive path to the transmit-receive switch in a receive mode of the radio and connect the transmit path to the transmit-receive switch in a transmit mode of the radio, wherein:
the transmit path comprises:
a frequency synthesizer configured to generate an output clock signal;
a local oscillator generator configured to generate a local oscillator signal based on the output clock signal;
and
a power amplifier connected to the transmit-receive switch and configured to amplify the local oscillator signal to generate a transmit signal;
and
the frequency synthesizer comprises:
a digitally controlled oscillator configured to generate the output clock signal based on a digital control word;
a clock divider configured to divide the output clock signal to generate a divided clock signal;
a digital-to-time converter configured to generate a feedback clock signal based on the divided clock signal;
a time-to-digital converter configured to generate a phase error signal based on a bias control word and a phase difference between a reference clock signal and the feedback clock signal;
a loop filter connected to the time-to-digital converter and configured to generate the digital control word based on the phase error signal;
and
a calibration unit configured to:
generate a training sequence;
generate a gain error signal by utilizing the training sequence;
and
modify the bias control word based on the gain error signal to generate a modified bias control word.

21 more elements

Dependencies are inferred from the claim text.

Radio transmitter

Life of this patent

Radio transmitter

Life of this patent

Abstract

Claims20