A radar system includes: a plurality of first receiving devices for generating a plurality of first digital signals according to a plurality of first incoming signals, respectively; and a plurality of second receiving devices for generating a plurality of second digital signals according to a plurality of second incoming signals, respectively. A processing device is arranged to perform a first beamforming operation to generate a plurality of first beamforming signals according to the plurality of first digital signals and a first gain matrix, and to perform a second beamforming operation to generate a plurality of second beamforming signals according to the plurality of second digital signals and a second gain matrix; and to determine an altitude angle of a first object and a second object, and to determine a first azimuth angle of the first object and a second azimuth angle of the second object.

A radar system includes: a processing device arranged to generate a plurality of phase shifting digital signals; a plurality of transmitting devices for generating an RF beam according to the plurality of phase shifting digital signals during a first mode; a plurality of first receiving devices for generating a plurality of first digital signals according to a plurality of first incoming signals, respectively, during a second mode; and a plurality of second receiving devices for generating a plurality of second digital signals according to a plurality of second incoming signals, respectively, during the second mode. The processing device is further arranged to distinguish a first object and a second object when the RF beam hits the first object and the second object, and the first object and the second object have a same radial speed and are located at a same range.

A counter signal counting at a frequency of a clock signal is generated. Among a plurality of different numeric ranges corresponding to a plurality of different thresholds, a threshold corresponding to a numeric range containing a frequency ratio is selected. In response to the counter signal reaching the selected threshold, a logic level of an output signal is switched.

A frequency divider circuit includes a counter configured to generate a counter signal responsive to a frequency of a clock signal and a frequency ratio, and a compensation circuit coupled to the counter, and configured to generate an output signal. The output signal has a frequency equal to the frequency of the clock signal divided by a frequency ratio, and a duty cycle lower than 50% and greater than 1/r, where r is the frequency ratio.

A frequency divider circuit includes: a first frequency dividing circuit configured to divide a first clock signal to generate a first frequency-divided clock signal; a second frequency dividing circuit configured to divide a second clock signal having the same frequency as the first clock signal and having a first phase difference with respect to the first clock signal to generate a second frequency-divided clock signal; a detection circuit configured to detect a phase relationship between the first frequency-divided clock signal and the second frequency-divided clock signal; and a selection circuit configured to select and output one of the second frequency-divided clock signal and an inverted signal of the second frequency-divided clock signal which are generated by the second frequency dividing circuit, based on the phase relationship between the first frequency-divided clock signal and the second frequency-divided clock signal detected by the detection circuit.

A radar system includes: a processing device arranged to generate a plurality of phase shifting digital signals; a plurality of transmitting devices for generating an RF beam according to the plurality of phase shifting digital signals during a first mode; a plurality of first receiving devices for generating a plurality of first digital signals according to a plurality of first incoming signals, respectively, during a second mode; and a plurality of second receiving devices for generating a plurality of second digital signals according to a plurality of second incoming signals, respectively, during the second mode. The processing device is further arranged to distinguish a first object and a second object when the RF beam hits the first object and the second object, and the first object and the second object have a same radial speed and are located at a same range.

A signal divider includes: a dividing circuit arranged to generate an output oscillating signal according to a first input oscillating signal; and a signal generating circuit, coupled to the dividing circuit, for generating an injection signal to the dividing circuit. The dividing circuit is arranged to generate the output oscillating signal with a predetermined phase according to the injection signal and the first input oscillating signal.

A frequency divider circuit includes a counter configured to generate a counter signal responsive to a frequency of a clock signal and a frequency ratio, and a compensation circuit coupled to the counter, and configured to generate an output signal. The output signal has a frequency equal to the frequency of the clock signal divided by a frequency ratio, and a duty cycle greater than 1/r, where r is the frequency ratio.

A divider and buffer circuit uses a receive command to initiate a reset of buffer circuitry prior to restarting to avoid a metastable state. For example, the divider and buffer circuit includes a first buffer circuit, a second buffer circuit, and a reset circuit. The reset circuit receives a command and provide a pulse on a reset signal in response to the command. In response to the reset pulse, the first buffer circuit provides a first divided clock signal having a first logical value based on respective logical values of received complementary clock signals and the second buffer circuit provides a second divided clock signal having a second logical value based on the respective logical values of the complementary clock signals. The command is a CAS SYNC command, in some examples.

A frequency divider circuit includes: a first frequency dividing circuit configured to divide a first clock signal to generate a first frequency-divided clock signal; a second frequency dividing circuit configured to divide a second clock signal having the same frequency as the first clock signal and having a first phase difference with respect to the first clock signal to generate a second frequency-divided clock signal; a detection circuit configured to detect a phase relationship between the first frequency-divided clock signal and the second frequency-divided clock signal; and a selection circuit configured to select and output one of the second frequency-divided clock signal and an inverted signal of the second frequency-divided clock signal which are generated by the second frequency dividing circuit, based on the phase relationship between the first frequency-divided clock signal and the second frequency-divided clock signal detected by the detection circuit.