Temperature-stable FBAR transmitter

• US 10,419,255 B2
• Filed: 09/04/2018
• Issued: 09/17/2019
• Est. Priority Date: 08/15/2016
• Status: Active Grant

• Current Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Original Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Inventors: Wiser, Robert Francis, Yeager, Daniel, Schauer, Justin, Sankaragomathi, Kannan Aryaperumal
• Primary Examiner(s): Fan, Chieh M
• Assistant Examiner(s): Hailegiorgis, Fitwi Y
• Application Number:
  US16/121,607
• Publication Number:
  US 20190007245A1
• Time in Patent Office: 378 Days
• Field of Search: 375295, 375296, 370281
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04L 27/125 using a controlled oscillator in an open loop
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication

Abstract

The present disclosure relates to a method that includes calculating a first frequency drift associated with an oscillator at a current temperature; based on the calculation, generating a first signal indicative of temperature compensation data; generating a second signal indicative of packet data and a modulation scheme; using the first signal, the second signal, and a first predetermined signal to generate a first tuning signal; and using the first tuning signal to tune a first capacitor array coupled to the oscillator and a second tuning signal to tune a second capacitor array coupled to the oscillator such that (i) the oscillator generates a modulated RF signal indicative of the packet data and (ii) the modulated RF signal has a second frequency drift that is less than a threshold.

Claims

1. A method comprising:

calculating a frequency drift associated with an oscillator at a current temperature;

based on the calculation, generating a first signal indicative of temperature compensation data;

generating a second signal indicative of packet data and a modulation scheme;

using the first signal and the second signal to generate a tuning signal; and

using the tuning signal to tune a capacitor array coupled to the oscillator such that (i) the oscillator generates a modulated RF signal indicative of the packet data and (ii) the modulated RF signal has a second frequency drift that is less than a threshold.

2. The method of claim 1, wherein the oscillator is a Pierce oscillator comprising a thin-film bulk acoustic resonator (FBAR).

3. The method of claim 1, wherein the modulation scheme is Gaussian Frequency Shift Keying (GFSK).

4. The method of claim 1, wherein the frequency drift is calculated based on the current temperature, a turnover temperature, and a gain coefficient.

5. The method of claim 4, wherein generating the second signal indicative of the packet data and the modulation scheme comprises:

generating a serialized data stream based on the packet data;

whitening the serialized data stream;

filtering the whitened data stream using a Gaussian filter; and

multiplying the filtered data stream by a predetermined signal to generate the second signal, wherein the predetermined signal is indicative of a frequency deviation of the modulation scheme.

6. The method of claim 5, wherein the predetermined signal, the turnover temperature, and the gain coefficient are predetermined using an off-chip two-point calibration process.

7. The method of claim 1, wherein the modulated RF signal comprises advertising packets.

8. A broadcasting unit comprising:

an oscillator;

a capacitor array coupled to the oscillator;

a temperature sensor;

a controller comprising a processor programmed to;

calculate a frequency drift associated with the oscillator at a current temperature;

based on the calculation, generate a first signal indicative of temperature compensation data;

generate a second signal indicative of packet data and a modulation scheme;

use the first signal and the second signal to generate a first tuning signal; and

use the first tuning signal to tune the capacitor array such that (i) the oscillator generates a modulated RF signal indicative of the packet data and (ii) the modulated RF signal has a second frequency drift that is less than a threshold.

9. The broadcasting unit of claim 8, wherein the oscillator is a Pierce oscillator comprising a thin-film bulk acoustic resonator (FBAR).

10. The broadcasting unit of claim 8, wherein the modulation scheme is Gaussian Frequency Shift Keying (GFSK).

11. The method of claim 8, wherein the frequency drift is calculated based on the current temperature, a turnover temperature, and a gain coefficient.

12. The broadcasting unit of claim 11, wherein generating the second signal indicative of the packet data and the modulation scheme comprises the controller configured to:

generate a serialized data stream based on the packet data;

whiten the serialized data stream;

filter the whitened data stream using a Gaussian filter; and

multiply the filtered data stream by a predetermined signal to generate the second signal, wherein the predetermined signal is indicative of a frequency deviation of the modulation scheme.

13. The broadcasting unit of claim 12, wherein the predetermined signal, the turnover temperature, and the gain coefficient are predetermined using an off-chip two-point calibration process.

14. The broadcasting unit of claim 8, wherein the modulated RF signal comprises advertising packets.

15. A system comprising:

a sensor;

a transceiver coupled to the sensor, the transceiver comprising;

an oscillator comprising a thin-film bulk acoustic resonator (FBAR);

a capacitor array coupled to the oscillator;

a temperature sensor; and

an antenna;

a controller comprising a processor programmed to;

calculate a frequency drift associated with the oscillator at a current temperature;

based on the calculation, generate a first signal indicative of temperature compensation data;

generate a second signal indicative of packet data and a modulation scheme;

use the first signal and the second signal to generate a tuning signal; and

use the tuning signal to tune the capacitor array such that (i) the oscillator generates a modulated RF signal indicative of the packet data and (ii) the modulated RF signal has a second frequency drift that is less than a threshold.

16. The system of claim 15, wherein the oscillator is a Pierce oscillator comprising a thin-film bulk acoustic resonator (FBAR).

17. The system of claim 15, wherein the modulation scheme is Gaussian Frequency Shift Keying (GFSK).

18. The system of claim 15, wherein the frequency drift is calculated based on the current temperature, a turnover temperature, and a gain coefficient.

19. The system of claim 18, wherein generating the second signal indicative of the packet data and the modulation scheme comprises the controller configured to:

generate a serialized data stream based on the packet data;

whiten the serialized data stream;

filter the whitened data stream using a Gaussian filter; and

multiply the filtered data stream by a predetermined signal to generate the second signal, wherein the predetermined signal is indicative of a frequency deviation of the modulation scheme.

20. The system of claim 15, wherein the packet data is based on an output of the sensor.