Abstract: 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(30) and supplying an amplified phase modulation component to a differential input of the differential power amplifier circuitry(30). A bias input of the differential power amplifier circuitry(30) is controlled based on the amplitude modulation component, so as to modulate a common-mode current of the differential power amplifier circuitry(30). 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.

Abstract: 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.

Abstract: 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(30) and supplying an amplified phase modulation component to a differential input of the differential power amplifier circuitry(30). A bias input of the differential power amplifier circuitry(30) is controlled based on the amplitude modulation component, so as to modulate a common-mode current of the differential power amplifier circuitry(30). 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.

Abstract: 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.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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?).

Abstract: A mixer circuit (102) for use in radio frequency (RF) equipment is disclosed. The mixer comprises a current source (Io) and a differential amplifier (Q1, Q2) connected to the current source and having input terminals (RF+, RF?) for receiving an RF input signal and output terminals (IF+, IF?) for providing an intermediate frequency signal. A local oscillator signal (LO) is applied to a transistor (Q3) connected in parallel with the differential amplifier to adjust the current flowing in the differential amplifier such that the differential output signal contains components having frequencies at the sum and difference frequencies of the RF and local oscillator signals. Emitter degeneration resistors (R1) and a transistor Q4 for diverting part of the current to the supply improve the linearity of the mixer.

Abstract: A sub-harmonic mixer circuit having an input stage (52) and a current modulating stage (64 is disclosed. The input stage (52) receives an RF input signal (RF+, RF?) at a first frequency and generates output currents (il , i2) varying in dependence upon the Rf input signal. The current modulating stage (64) comprises a first transistor (Q3) for receiving a first local oscillator signal (LO0) respective and a second transistor (Q4) for receiving a second local oscillator signal (LO180), 180 degrees out of phase with the first local oscillator signal, such that a modulating current signal (iO), having twice the local oscillator frequency is superimposed onto the output currents.

Abstract: 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 (30) and supplying an amplified phase modulation component to a differential input of the differential power amplifier circuitry (30). A bias input of the differential power amplifier circuitry (30) is controlled based on the amplitude modulation component, so as to modulate a common-mode current of the differential power amplifier circuitry (30). 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.

Abstract: 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.

Abstract: 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).

Abstract: A subharmonic mixer circuit having an input stage (52) and a current modulating stage (64) is disclosed. The input stage (52) receives an RF input signal (RF+, RF?) at a first frequency and generates output currents (i1, i2) varying in dependence upon the Rf input signal. The current modulating stage (64) comprises a first transistor (Q3) for receiving a first local oscillator signal (LOO) respective and a second transistor (Q4) for receiving a second local oscillator signal (LOI 80), 180 degrees out of phase with the first local oscillator signal, such that a modulating current signal (i0), having twice the local oscillator frequency, is superimposed onto the output currents.

Abstract: 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?).

Abstract: In a receiver for receiving a modulated carrier (MC) having asymmetrical sidebands (USB,LSB), for example, a TV signal, a synchronous demodulator (SDEM) derives a vectorial baseband signal (VB) from the modulated carrier (MC). A filter (FILT) filters the vectorial baseband signal so as to compensate for the sideband asymmetry, for example, by means of a Nyquist slope. Thus, the sideband asymmetry is compensated at baseband frequencies, rather than at an intermediate frequency, which allows a better quality of reception.

Abstract: In a receiver the input signal is converted by a mixer into two quadrature IF signals. The quadrature IF signals are amplified by an amplifier and filtered by a filter. A polyphase filter suppresses signals having frequencies above a predetermined frequency. A second mixer converts the filtered IF signal into a second IF signal. This second IF signal is filtered by a second polyphase filter which suppresses signals having a frequency below a predetermined frequency. In this way a band-pass transfer function is obtained having a first edge defined by the first polyphase filter and having the second defined by the second polyphase filter. In an embodiment of the invention, the cut off frequencies of the polyphase filters are equal to zero, resulting in a transfer function for the complete receiver having cut off frequencies independent from the component values use in the polyphase filters.

Abstract: In a diode mixer circuit MIX, a driving circuit DRIV produces a first, second, third and fourth drive signal DS1, DS2, DS3, DS4. Each drive signal is a combination of a first and a second input signal LO, RF with the following signs: DS1: +LO+RF DS2: +LO−RF DS3: −LO+RF DS4: −LO−RF A first, second, third and fourth diode D1, D2, D3, D4 transfer the first, second, third and fourth drive signal DS1, DS2, DS3, DS4 respectively, to an output O1. The first and fourth diodes D1, D4 have the same polarity relative to the output. The second and third diodes D2, D3 also have the same polarity relative to the output, but opposite to that of the first and fourth diodes D1, D4. A mixer circuit of this type is suitable for a relatively large variety of applications, notably because it may be realized in the form of an integrated circuit.

Abstract: A current amplifier A1 includes two transistors Q1 and Q2 whose emitters are interconnected via a resistor R1. The input of the current amplifier is constituted by the emitter of the first transistor Q1, whose collector is connected to the output terminal of the amplifier A1 via a second resistor R2, and to the first resistor R1 via the main current path of the second transistor Q2. The current amplifier A1 has a simple structure and a low input impedance, as well as an easily controllable gain.

Abstract: 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.