摘要:
A low power frequency synthesizer circuit for a radio transceiver, the synthesizer circuit comprising: a digital controlled oscillator configured to generate an output signal (Fo) having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an input of the digital controlled oscillator, the feedback loop configured to provide the digital control word to the input of the digital controlled oscillator from an error derived from an input frequency control word (FCW) and the output signal; and a duty cycle module connected to the digital controlled oscillator and the feedback loop, the duty cycle module configured to generate a plurality of control signals to periodically enable and disable the digital controlled oscillator for a set fraction of clock cycles of an input reference clock signal (RefClock).
摘要:
A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator (33) configured to generate an output signal (F0) having a frequency controlled by an input digital control word (DCW); a feedback loop (35-38) connected between an output and an input of the digital controlled oscillator, the feedback loop configured to provide the digital control word to the input of the digital controlled oscillator from an error derived from an input frequency control word (FCW) and the output signal; and a duty cycle module (32) connected to the digital controlled oscillator and the feedback loop, the duty cycle module configured to generate a plurality of control signals to periodically enable and disable the digital controlled oscillator for a set fraction of clock cycles of an input reference clock signal (RefClock).
摘要:
A frequency divider includes a first latch and a second latch. The first latch is configured to receive a clock signal. The first latch is cross-coupled to the second latch. The second latch includes a circuit configured as a low-pass filter. The second latch further includes a differential pair of transistors. Each of the transistors include a drain, a source and a gate. The gates of the at least two transistors configured to receive a signal generated by the first latch. Additionally, the gates of the at least two other transistors are coupled to a control signal for determining a low-pass characteristic of the second latch.
摘要:
A frequency divider comprising, a first latch circuit and a second latch circuit, the second latch circuit being crossed-coupled to the first latch circuit. Each latch comprises a respective sense amplifier coupled to a respective latch. The sense amplifiers comprise a first clock input for receiving a first clock signal. The latches comprise a second clock input for receiving a second clock signal having a second frequency, the second frequency being substantially double the first frequency.
摘要:
A frequency divider comprising, a first latch circuit (10) and a second latch circuit (10), the second latch circuit (10′) being crossed-coupled to the first latch circuit (10). Each latch (10; 10′) comprises a respective sense amplifier coupled to a respective latch (11). The sense amplifiers comprise a first clock input for receiving a first clock signal (f, f) and 5 respective complementary first clock signal having a first frequency. The latches (11) comprise a second clock input (2f; 2f) for receiving a second clock signal and respective complementary second clock signal having a second frequency, the second frequency being substantially double the first frequency.
摘要:
Control circuitry and method of controlling for a sampling phase lock loop (PLL). By controlling the duty cycle of one or more sampling control signals, power consumption by the reference signal buffer and spurious output signals from the sampling PLL being controlled can be reduced.
摘要:
A two-wire interface for a digital microphone circuit includes a power line and a ground line. The interface utilizes the ground line as a “voltage active line” to transmit both clock and data signals between the digital microphone circuit and a receiving circuit. The digital microphone circuit detects the clock signal on the voltage active line and uses the detected clock signal to operate an ADC to provide digital data. The digital data is used to selectively drive current back to the receiving circuit over the voltage active line. The receiving circuit detects the transmitted data by monitoring the voltage associated with a line termination. The impedance associated with the line termination is switched by the receiver circuit to modulate the clock signal on the voltage active line.
摘要:
A line driver comprising a first transistor (M1), a first operational transconductance amplifier (A1) and a reference resistor (10) for converting an input voltage (Vin) to a first current (i1) through the first transistor (M1). A second current i2=n*i1 flows through a second transistor (M2) which forms a 1:n current mirror with the first transistor (M1). The current i2 flows to a load (6), if so required via a transmission line (TL). The impedance of the load (6) is equal to the characteristic impedance RL of the transmission line (TL). Thus, the impedance seen by the line driver is equal to RL. A second operational transconductance amplifier (A2) counteracts reflected signals in the output signal (Vout) caused by mismatch between the output impedance of the current mirror (M1, M2) and the impedance seen by the line driver.
摘要翻译:一种线驱动器,包括第一晶体管(M1),第一操作跨导放大器(A1)和参考电阻器(10),用于通过第一晶体管(M1)将输入电压(Vin)转换为第一电流(i1)。 第二电流i2 = n * i1流过与第一晶体管(M1)形成1:n电流镜的第二晶体管(M2)。 如果通过传输线(TL)需要,电流i2流向负载(6)。 负载(6)的阻抗等于传输线(TL)的特性阻抗RL。 因此,线路驱动器看到的阻抗等于RL。 第二运算跨导放大器(A2)抵消了由电流镜(M1,M2)的输出阻抗与线路驱动器所看到的阻抗之间的失配引起的输出信号(Vout)中的反射信号。
摘要:
An electrically controllable oscillator circuit (30) comprises two balanced transconductance circuits (G1, G2), each including transistor pairs arranged as inverters (Inv14) and as resistors (Inv5-6). The oscillation frequency (f) and the quality factor (Q) of the oscillator circuit (30) are controlled by means of a single control signal provided by a combined control circuit (Inv7, Dif, IM1, IM2). The current mirror circuit (IM1, IM2) and a differential pair (Dif) derived the control signal for adjusting the quality factor (Q) from a resistor-connected further transistor pair (Inv7) connected to the control signal for adjusting the frequency (f). The quality factor of an electrically controllable filter arangement including similar transconductance circuits (G-3-9) is adjusted by means of the control signal generated by the control circuit via a buffer circuit (B) and a low-pass circuit (C3).
摘要:
Control circuitry and method of controlling for a sampling phase lock loop (PLL). By controlling the duty cycle of a sampling control signal, in accordance with the PLL reference and output signals, spurious output signals from the sampling PLL being controlled can be reduced.