Abstract: A communication system for determining a target calibration parameter for calibrating impairments in a transmission signal is disclosed. The communication system includes a carrier signal generator, a transmitting module, a testing signal generator, a power detection unit, and a calibration apparatus. The testing signal generator generates a first testing signal to the first transmitting path of the transmitting module or a second testing signal to the second transmitting path of the transmitting module according to a single tone signal having a specific frequency or according to combinations of a DC value and the single tone signal. The power detection unit detects power of components associated with the specific frequency in the transmission signal to generate a power indicating signal. The calibration apparatus applies a first candidate calibration parameter to reference a first power indicating signal corresponding to the first candidate calibration parameter to determine the target calibration parameter.

Abstract: A charge pump circuit is disclosed, including: a dummy current path comprising a first junction node; a normal current path comprising a second junction node; a switch, coupled between the dummy current path and the normal current path; wherein when the switch is closed a first voltage is at the first junction node and the second junction node, and when the switch is open a second voltage is at the first junction node; and a comparator, for comparing the first voltage and the second voltage to balance a current mismatch of the charge pump circuit. The disclosed charge pump circuit can be implemented in a phase locked loop system.

Abstract: A charge pump circuit is disclosed, including: a dummy current path comprising a first junction node; a normal current path comprising a second junction node; a switch, coupled between the dummy current path and the normal current path; wherein when the switch is closed a first voltage is at the first junction node and the second junction node, and when the switch is open a second voltage is at the first junction node; and a comparator, for comparing the first voltage and the second voltage to balance a current mismatch of the charge pump circuit. The disclosed charge pump circuit can be implemented in a phase locked loop system.

Abstract: A communication system for determining a target calibration parameter for calibrating impairments in a transmission signal is disclosed. The communication system includes a carrier signal generator, a transmitting module, a testing signal generator, a power detection unit, and a calibration apparatus. The testing signal generator generates a first testing signal to the first transmitting path of the transmitting module or a second testing signal to the second transmitting path of the transmitting module according to a single tone signal having a specific frequency or according to combinations of a DC value and the single tone signal. The power detection unit detects power of components associated with the specific frequency in the transmission signal to generate a power indicating signal. The calibration apparatus applies a first candidate calibration parameter to reference a first power indicating signal corresponding to the first candidate calibration parameter to determine the target calibration parameter.

Abstract: A searching method for determining a function associated with a memory block of a memory of a computer system and the computer system thereof are disclosed. A first function execution code executed by the computer system calls a second function execution code to require the computer system to allocate a first memory block to the first function execution code. A symbol mapping table (i.e., a linker map) stores a symbol address corresponding to the first function execution code. The searching method includes storing a return address of the second function execution code into a predetermined memory block of the memory, reading the return address from the predetermined memory block, and determining that the first memory block has been allocated to the first function execution code according to the return address and the symbol address stored in the symbol mapping table.

Abstract: A method for finding a function call stack when a computer system executes a function in run time includes obtaining a program counter generated from executing the function, obtaining a corresponding instruction according to the program counter, detecting whether the instruction corresponds with a Push-LR-to-Stack instruction, and storing an instruction address pointed to by the program counter when the instruction corresponds with the Push-LR-to-Stack instruction.

Abstract: A quadrature modulator and a transmitter capable of detecting and reducing a current offset are provided. The quadrature modulator comprises a base band transconductance for converting a voltage signal into a current signal and a switching pair for modulating the current signal. A current sink is further coupled after the base band transconductance for detecting a current offset of the current signal. When the current sink is enabled to detect the current offset of the transmitter within a predetermined time interval, the switching pair is disabled, and after the predetermined time interval lapses, the current sink is disabled and the switching pair is enabled.