39 results about "Dual-modulus prescaler" patented technology

Disclosed is a Dual-Modulus Prescaler (DMP) dividing an input signal into an output signal, comprising: a synchronous counter, including a D-Flip-Flop (DFF), a first NOR-Flip-Flop and a second NOR-Flip-Flop, receiving the input signal, the division ratio thereof being based on an intermediate signal; a control logic, controlling the division ratio of the synchronous counter and selecting the output frequency based on first and second control signals, and outputting the intermediate signal to the synchronous counter; and an asynchronous counter, coupled to the control logic and the synchronous counter, having a chain of five DFFs.

The dual-modulus prescaler circuit (1) is devised to operate at a very high frequency. This circuit includes an assembly formed of two dynamic D-type flip flops (12, 13), and two NAND logic gates (15, 16) arranged in negative feedback between the two flip flops. The two flip flops are clocked by an input clock signal (CK) to supply a divided output signal (OUT) whose frequency matches the input clock frequency divided by 2 or by 3 as a function of a division mode selection signal (divb) applied to the input of the first NAND logic gate (15). One non-inverted output of the second flip flop is connected to one input of the first flip flop (12). The first dynamic flip flop includes three active branches and supplies a single inverted output signal. A third flip flop (14) with three active branches receives an inverted mode selection signal (div) at input in order to supply the mode selection signal to the inverted output thereof, clocked by the non-inverted output signal of the second flip flop.

A frequency divider is disclosed. The frequency divider includes a multi-modulus prescaler to perform a frequency division by a modulus M, wherein M is an integer between N and 2*N−1 and N is a power of 2. The frequency divider also includes a programmable counter to output the digital representation of M and an output clock signal. For the frequency divider, M equals N plus D minus D\N for each edge of the multi-modulus prescaler output clock CKpr wherein the counter samples the digital representation of D and D\N denotes an integer part of D divided by N, and M equals N for each subsequent edge of the prescaler output clock CKpr wherein the counter does not sample the digital representation of D.

The invention discloses a high speed high-oscillation amplitude divide-by-two frequency divider circuit, which belongs to the technical fields of integrated circuit designing and signal processing. Specifically, the circuit mainly comprises two high speed high-oscillation amplitude D triggers which are cascaded. The D trigger of each stage eliminates the bias of a tail current source based on theconventional D trigger having a current-mode logic (CML) structure, and adopts a P-channel metal oxide semiconductor (PMOS) transistor as a load; and simultaneously, a PMOS and N-channel metal oxide semiconductor (NMOS) complementary cross coupling pair structure and the like are adopted by the output stage of the circuit to finally achieve the aims of increasing the oscillation amplitude of an output signal and making the oscillation amplitude of the output signal approximate to full oscillation amplitude under the condition of ensuring the high speed working of the circuit. The circuit not only can directly drive a post circuit, reduces system power consumption to a certain extent, compensates for the shortcomings of a conventional divide-by-two frequency divider, and is suitable for a high speed frequency divider part in a low-power consumption preposed dual-mode prescaler front-end without any additional level conversion amplification circuit.

A phase-switching dual modulus prescaler having a dual modulus divider is provided. Said divider comprises a first and second divide-by-2 circuit (A;B), wherein said second divide-by-2 circuit (B) is coupled to the output of said first divide-by-2 circuit (A) and at least said second divide-by-two circuit (B) comprises a four phase output each separated by 90°. A phase selection unit (PSU) is provided for selecting one of the four phase outputs (Ip, In, Qp, Qn; INi, INni, INq, Innq) of the second divide-by-2 circuit (B). Moreover, a phase control unit is provided for providing control signal (C1, NC0; C2, NC2; C3, NC3) to the phase selection unit, wherein the phase selection unit (PSU) performs the selection of the four phase outputs (Ip, In, Qp, Qn; INi, INni, INq, Innq) according to the control signals (C0, NC0; C1, NC1; C2, NC2). Said phase selection unit (PSU) is implemented based on direct logic. The implementation of the phase selection unit based on direct logic enables a higher speed and saves area on the chip.

The invention discloses a 2 / 3 dual-mode prescaler with high speed and low power consumption, which includes two D flip-flops, which are respectively marked as flip-flop DFF1 and flip-flop DFF2, and the working state of flip-flop DFF1 is controlled by the frequency division mode Signal MC control, the first stage of flip-flop DFF2 adopts E-TSPC circuit with dynamic floating input to improve circuit speed, and the second and third stages adopt dynamic D latch with TSPC structure to further reduce power consumption; when MC= When 1, flip-flop DFF1 does not work, flip-flop DFF2 works normally, and the 2 / 3 dual-mode prescaler works in 2 frequency division mode; when MC=0, flip-flop DFF1 works normally, flip-flop DFF2 works normally, 2 The / 3 dual-mode prescaler operates in divide-by-three mode. The invention has simple circuit structure, small jitter of the output frequency division signal, high working frequency and wide frequency division range.