摘要:
The present invention relates to an oscillator circuit and a method of controlling the oscillation frequency of an in-phase signal and a quadrature signal. First oscillator means (2) with a first differential oscillator circuit and a first differential coupling circuit are provided for generating the quadrature signal. Furthermore, second oscillator means (4) with a second differential oscillator circuit and a second differential coupling circuit are provided for generating the in-phase signal. A frequency control means is provided for varying the oscillation frequency of the in-phase signal and the quadrature signal by controlling at least one of a common-mode current and a tail current of the first and second oscillator means. Thereby, a high-frequency IQ oscillator with high linearity is obtained.
摘要:
The present invention relates to a polar modulation apparatus and method, in which a polar-modulated signal is generated based on separately processed phase modulation (PM) and amplitude modulation (AM) components of an input signal. An amplified polar modulated output signal is generated in accordance with the phase modulation and amplitude modulation components by using a differential power amplifier circuitry and supplying an amplified phase modulation component to a differential input of the differential power amplifier circuitry. A bias input of the differential power amplifier circuitry is controlled based on the amplitude modulation component, so as to modulate a common-mode current of the differential power amplifier circuitry. Thereby, a new concept of a polar modulator with static DC-DC converter and power and/or efficiency and/or linearity controlled output power amplifier can be achieved.
摘要:
Devices (1,2) comprising feedback-less amplifiers (16,19,26,29) that are gain controlled introduce linear relationships between output signals and input signals of the feedback-less amplifiers (16,19,26,29) by providing the feedback-less amplifiers (16,19,26,29) sub-circuits in the form of first transistors (33) operated in their triode regions for receiving input signals and second sub-circuits in the form of second transistors (34) for receiving control signals and third sub-circuits in the form of resistors (35) for generating output signals, whereby the respective first and second and third sub-circuits form a serial path. Second circuits (4) receive gain signals and convert the gain signals into the control signals. The control signals are copies of the gain signals. The second circuits (4) comprise current sources (6) and third and fourth transistors (41,42). The current sources (6) comprise fifth and sixth transistors (61,62). The second circuits (4) further comprise voltage sources (9) further current sources. Third circuits (8) compensate common mode currents.
摘要:
A BALUN circuit (20) for low voltage operation for receiving single ended input signal at an input terminal (24) and providing a differential output signal across a pair of output terminals (OUT+, OUT−) is disclosed. The BALUN circuit (20) comprises a first branch including an input terminal (24) for receiving a single ended input voltage signal (RFin), a transistor (Q1), a resistance (R1) (28), a resistance (RL), and an output terminal (OUT+). A second branch includes a transistor (Q3), a resistance (RL) and an output terminal (OUT−). An operational amplifier (26) maintains current flowing through the resistances RL in the first and second branches substantially equal to each other, in dependence upon the output voltage signal across the output terminals (OUT+, OUT−).
摘要:
A tunable balanced RC filter circuit of the type in which the resistors are formed as MOS transistors with variable gate voltages for tuning the filter. The MOS transistor takes the form of a series arrangement of individual MOS transistors (T1-1, T1-2, . . . , T1-N; T2-1, T2-2, . . . , T2-N) each having the same d.c. bias on its gate. The gate of each of the individual MOS transistors in the series arrangement also receives a fraction of the a.c. component of the input signal on the input terminals (IT1, IT2) of the two-port network by means of a resistor ladder (R1-1, R1-2, . . . , R1-N, R2-1, R2-2, . . . , R2-N), which is connected to the input terminals (IT1, IT2) via buffers (B1, B2). The a.c. component of the input signal is thus divided among the individual transistors in the series arrangement. In this way it is possible to use MOS transistors with a small gate voltage swing at comparatively large input voltages.
摘要:
A digital dynamic range converter of the forward control type for varying the dynamic range of a digital audio signal constituted by a sequence of audio signal samples. Each audio signal sample x(n) is multiplied by a control signal sample s(n) which is delivered by a digital control signal generator. This control signal generator has applied to it unipolar signal samples x(n) which are derived via a transmission channel from the audio signal samples x(n). In order to cause this dynamic range converter to respond rapidly to abrupt variations in the audio signal and to render it moreover universally usable, the control signal generator is provided with a digital peak-value detector which converts the sequence of unipolar signal samples x(n) into a sequence of peak-value samples x(n). The latter are applied to a digital non-linear amplitude transformation circuit which has an adjustable amplitude transmission characteristic curve determined by adjustment quantities R and a. It delivers the transformation samples s(n) which are preferably converted in a digital low-pass filter into the control signal samples s(n) which are applied to the multiplier device.
摘要:
The present invention relates to an oscillator circuit and a method of controlling the oscillation frequency of an in-phase signal and a quadrature signal. First oscillator means (2) with a first differential oscillator circuit and a first differential coupling circuit are provided for generating the quadrature signal. Furthermore, second oscillator means (4) with a second differential oscillator circuit and a second differential coupling circuit are provided for generating the in-phase signal. A frequency control means is provided for varying the oscillation frequency of the in-phase signal and the quadrature signal by controlling at least one of a common-mode current and a tail current of the first and second oscillator means. Thereby, a high-frequency IQ oscillator with high linearity is obtained.
摘要:
The present invention provides a driving circuit (100) in particular for driving a laser diode (700) or a modulator, at data speed in the order of Gb/s. The driving circuit (10) has a low-voltage, high-speed output stage capable of driving efficiently a laser diode (700) or a modulator The driver circuit (10) comprises a chain of circuits, said chain comprising a slew-rate control circuit, at least one translinear amplifier (200, 201, 202), a push/pull stage (300), and an output stage (400) for driving the load current. Due to its versatility, the driver can be used in other applications e.g. line drivers, cable drivers, high-speed serial interfaces for back-plane interconnect, etc. The driver can work at low supply voltages, e.g. 3.3V nominal down to 2.7V, with high power efficiency. One major clue is to use entirely the large signal current produced by the output stage, e.g. in the driven laser diode, without wasting current in supply lines.
摘要:
In a television receiver a SAW filter (FSAW) is preceded by a coupling network (CNW). The coupling network (CNW) includes an inductor (LP) between two input terminals of the SAW filter (IS1, IS2). It further includes a series resonance circuit (SRC) coupled to at least one of the input terminals (IS1). In order to reduce signal distortion a resistor (RP) is coupled between the two input terminals (IS1, IS2). Alternatively, a resistor (RS) is coupled in parallel to the series resonance circuit (SRC).
摘要:
Interpolating time-discrete filter arrangement for increasing the sampling frequency of a time-discrete signal from f.sub.i to f.sub.u, f.sub.u not being a rational multiple of f.sub.i. For the generation of the required filter coefficients this filter arrangement comprises clock pulse generators which produce input clock pulses ki(q) at a rate f.sub.i and output clock pulses ku(n) at a rate f.sub.u. It also comprises a coefficients generator in which a deviation component d(q) is calculated which indicates the relationship between the time interval T.sub.d(q) located between an input clock pulse k.sub.i (q) and the immediately preceding or the immediately subsequent output clock pulse ku(n) and the time interval T.sub.u =1/f.sub.u between two consecutive output clock pulses ku(n). In response to this deviation component the filter coefficients generator produces W filter coefficients, the w.sup.th filter coefficient (w=0, 1, 2, 3, . . . W-1) being equal to a(d(q),w) and being defined by the expressiona(d(q),w=h(d(q)T.sub.u +wT.sub.u)Herein the function h(v) represents the impulse response of a FIR filter and v a continuous variable in the interval -.infin.