Time gain compensation circuit and related apparatus and methods
An ultrasound device, including a profile generator, an encoder configured to receive a profile signal from the profile generator, and an attenuator configured to receive a signal representing an output of an ultrasound sensor and coupled to the encoder to receive a control signal from the encoder, the attenuator including a plurality of attenuator stages, the attenuator configured to produce an output signal that is an attenuated version of the input signal.
1. A handheld ultrasound probe, comprising:
ultrasound transducers configured to transmit ultrasound waves and to receive reflected ultrasound waves from a target;
receive circuitry coupled to the ultrasound transducers and configured to output a signal based on the received reflected ultrasound waves received by the ultrasound transducers;
a variable attenuator coupled to control circuitry and configured to receive the signal from the receive circuitry and to output an attenuated signal that varies with time based on control signals received from the control circuitry, the variable attenuator comprising a plurality of selectable attenuation circuits, wherein each of first and second attenuation circuits of the plurality of selectable attenuation circuits comprises a switch and a respective resistor, and wherein the switch is controllable by the control signals received from the control circuitry; and
digitizing circuitry configured to digitize the attenuated signal and to output a digitized signal.
2. The ultrasound probe of claim 1 , wherein the receive circuitry and the variable attenuator are located on a common substrate.
3. The ultrasound probe of claim 2 , wherein the ultrasound transducers are located on the common substrate.
4. The ultrasound probe of claim 1 , wherein:
the variable attenuator comprises first and second legs, and
the plurality of selectable attenuation circuits are arranged in parallel between the first and second legs.
5. The ultrasound probe of claim 4 , wherein each selectable attenuation circuit comprises a switch connected in series with first and second resistors, the switch being positioned between the first and second resistors.
6. The ultrasound probe of claim 4 , wherein each selectable attenuation circuit comprises a switch connected in series with a resistor.
7. The ultrasound probe of claim 1 , wherein:
the variable attenuator comprises first and second legs, and
the plurality of selectable attenuation circuits are arranged in series on the first leg.
8. The ultrasound probe of claim 7 , wherein the switch and respective resistor of each of the first and second attenuation circuits are in parallel with each other.
9. The ultrasound probe of claim 7 , wherein the plurality of selectable attenuation circuits is a first plurality of selectable attenuation circuits, and wherein the variable attenuator comprises a second plurality of selectable attenuation circuits arranged in series on the second leg.
10. The ultrasound probe of claim 9 , wherein each of the first plurality of selectable attenuation circuits and second plurality of selectable attenuation circuits comprises a resistor and a switch connected in parallel with the resistor.
11. A method of operation of a handheld ultrasound probe, comprising:
receiving, by ultrasound transducers of the ultrasound probe, ultrasound waves reflected from a target;
outputting, by receive circuitry coupled to the ultrasound transducers, a signal based on the received reflected ultrasound waves received by the ultrasound transducers;
attenuating, by a variable attenuator, the signal and outputting an attenuated signal that varies with time based on control signals received from control circuitry coupled to the variable attenuator, wherein the attenuating of the signal comprises controlling a plurality of selectable attenuation circuits of the variable attenuator, wherein each of first and second attenuation circuits of the plurality of selectable attenuation circuits comprises a switch and a respective resistor, and wherein the switch is controllable by the control signals received from the control circuitry; and
digitizing the attenuated signal and outputting a digitized signal.
12. The method of claim 11 , wherein the outputting and the attenuating occur on a common substrate.
13. The method of claim 12 , wherein the receiving occurs on the common substrate.
14. The method of claim 11 , wherein:
the variable attenuator comprises first and second legs, and
the plurality of selectable attenuation circuits are arranged in parallel between the first and second legs.
15. The method of claim 14 , wherein each selectable attenuation circuit comprises a switch connected in series with first and second resistors, the switch being positioned between the first and second resistors, and the switch being controllable by the control signals received from the control circuitry.
16. The method of claim 14 , wherein each selectable attenuation circuit comprises a switch connected in series with a resistor, the switch being controllable by the control signals received from the control circuitry.
17. The method of claim 11 , wherein:
the variable attenuator comprises first and second legs, and
the plurality of selectable attenuation circuits are arranged in series on the first leg.
18. The method of claim 17 , wherein each of the plurality of attenuation circuits comprises a resistor and a switch connected in parallel with the resistor, the switch being controllable by the control signals received from the control circuitry.
19. The method of claim 17 , wherein the plurality of selectable attenuation circuits is a first plurality of selectable attenuation circuits, and wherein the variable attenuator comprises a second plurality of selectable attenuation circuits arranged in series on the second leg.
20. The method of claim 19 , wherein each of the first plurality of selectable attenuation circuits and second plurality of selectable attenuation circuits comprises a resistor and a switch connected in parallel with the resistor.