CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0018807, filed on Feb. 18, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

The disclosure relates to analog beamformers.

2. Description of Related Art

An analog beamformer is a circuit for adjusting timing of a set of analog signals by adjusting a delay time for each of the analog signals. Analog beamformers have been used in various electronic devices employing a set of analog signals. Although an analog beamformer basically uses an input signal and a clock signal, unwanted frequency components may be contained in an output signal due to interference between the input and clock signals. The unwanted frequency components in the output signal may decrease a signal-to-noise ratio (SNR) of the output signal and thus degrade the quality thereof. Furthermore, the unwanted frequency components may adversely affect data components and thereby cause signal distortion.

Ultrasound imaging apparatuses transmit ultrasound signals generated by transducers of a probe to an object and receive information about signals reflected from the object, thereby obtaining at least one image of an internal part, for example, soft tissue or blood flow, of the object. Ultrasound imaging apparatuses process analog signals generated by a probe to obtain an ultrasound image, and include an analog beamformer for performing beamforming on the generated analog signals.

SUMMARY

Provided are analog beamformers for reducing unwanted signal components in their output signals.

Also provided are analog beamformers for reducing down-mixing components in their output signals.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, an analog beamformer includes: an input circuit configured to receive an input signal to generate a first input signal having the same phase as the input signal and a second input signal having a phase difference corresponding to a first phase with respect to the input signal; a first delay circuit configured to receive the first input signal and delay the first input signal by a beamforming delay time to output a first delayed signal; a second delay circuit configured to receive the second input signal and delay the second input signal by the beamforming delay time to output a second delayed signal; and an output circuit configured to output an output signal by summing the first delayed signal and the second delayed signal. In the analog beamformer, a first write signal controlling an input of the first delay circuit has the phase difference corresponding to the first phase with respect to a second write signal controlling an input of the second delay circuit, and a first read signal controlling an output of the first delay circuit has the phase difference corresponding to the first phase with respect to a second read signal controlling an output of the second delay circuit.

The first phase may correspond to 90 degrees.

The input circuit may be further configured to perform orthogonal transformation on the input signal, and the first input signal may be orthogonal to the second input signal.

The first delay circuit may be further configured to hold the first input signal in response to the first write signal and output the first delayed signal in response to the first read signal that is delayed by the beamforming delay time with respect to the first write signal, and the second delay circuit may be further configured to hold the second input signal in response to the second write signal and output the second delayed signal in response to the second read signal that is delayed by the beamforming delay time with respect to the second write signal. The second write signal may have the phase difference corresponding to the first phase with respect to the first write signal, and the second read signal may have the phase difference corresponding to the first phase with respect to the first read signal.

The analog beamformer may further include: a write signal generating circuit configured to generate the first write signal and the second write signal by performing orthogonal transformation on an original write signal; and a read signal generating circuit configured to generate the first read signal and the second read signal by performing orthogonal transformation on an original read signal.

The first delay circuit may include a plurality of first delay cells, each of which includes: a first write switch that is turned on in response to the first write signal and transmits the first input signal; a first capacitor storing the first input signal transmitted via the first write switch; and a first output switch that is turned on in response to the first read signal and outputs the first delayed signal from the first capacitor. The second delay circuit may include a plurality of second delay cells, each of which includes: a second write switch that is turned on in response to the second write signal and transmits the second input signal; a second capacitor storing the second input signal transmitted via the second write switch; and a second output switch that is turned on in response to the second read signal and outputs the second delayed signal from the second capacitor.

The first write signal may include a plurality of pulses respectively corresponding to the plurality of first delay cells, and the first read signal may include a plurality of pulses respectively corresponding to the plurality of first delay cells. The second write signal may include a plurality of pulses respectively corresponding to the plurality of second delay cells, and the second read signal may include a plurality of pulses respectively corresponding to the plurality of second delay cells.

Each of the first and second write signals may have a first clock frequency, and the output signal may include an up-mixing component having a frequency corresponding to a sum of an input frequency of the input signal and the first clock frequency and a down-mixing component having a frequency corresponding to a difference between the input frequency and the first clock frequency.

An intensity of the down-mixing component may be less than or equal to ten (10) percent of an intensity of the up-mixing component.

The analog beamformer may perform beamforming on an analog signal output from an ultrasound probe, and the input signal may include a plurality of signals output from a plurality of elements of a transducer in the ultrasound probe.

The analog beamformer may perform beamforming on an analog signal detected by a radar, and the input signal may include a plurality of signals output from a plurality of detecting elements of the radar.

The radar may be installed on a car to detect objects in the car's surroundings.

