摘要:
A device for multiplying a capacitance by a variable coefficient, for example for adjusting a cut-off frequency of a filter, includes a current amplifier for amplifying a current flowing through said capacitance. The capacitance is floating between first and second predetermined points. The current amplifier circuit includes a differential current amplifier.
摘要:
A current pulse generator device includes current pulse generator circuits and polarizer circuits. It further includes holding circuits for holding the polarization voltage connected to the generator circuits, the holding circuits connected via switch circuits to the polarizer circuits. The switch circuits can assume in succession a closed or adjustment position in which they connect the holding circuits to the polarizer circuits, and an open or operating position in which they isolate the holding circuits from the polarizer circuits so that the generator circuits generate at least one low-noise current pulse. The device can be used in a phase comparator and a radiocommunication terminal, and the phase comparator can be used in a synthesiser.
摘要:
The invention relates to a frequency divider of the type comprising a prescaler followed by a programmable counter, and serving to divide by an overall division ratio D that can be written D=k.N+A. The prescaler operates with a pair of division ratios k/k+1, and includes means for changing from the higher division ratio k+1 to the lower division ratio k as a function of a modulus control signal. N is a first predetermined programmable value corresponding to the division ratio of the programmable counter. A is a second predetermined programmable value such that on being reached by the programmable counter, the prescaler receives the modulus control signal. The following is true: 0.ltoreq.A
摘要翻译:本发明涉及一种分频器,其类型包括预分频器,其后面是可编程计数器,并且用于除以可写为D = k.N + A的总分频比D。 预分频器以一对分频比k / k + 1进行工作,并且包括作为模数控制信号的函数的从较高分频比k + 1到较低分频比k的装置。 N是与可编程计数器的分频比对应的第一预定可编程值。 A是第二预定可编程值,使得在由可编程计数器到达时,预分频器接收模数控制信号。 以下是真实的:0 = A
摘要:
Problems of noise emission during transmission in successive time slots (A-B) in mobile telephony are solved by causing the transmitted power to change in a monotonic manner from a previous value to a new value. It is shown that this increases the transmission bit rate.
摘要:
A transmit-receive system includes a phase-locked loop and a translation frequency loop. To bring about frequency hops, the frequencies in the two loops are varied with large increments in opposite directions. It is shown that the noise caused by the frequency division in the loops is thereby reduced.
摘要:
An audio receiver system including: a modulator (1) for modulating a first digital audio signal with a first modulation rate and a second digital audio signal including a plurality of 1-bit words over a predetermined period at a second modulation rate higher than the first modulation rate, and an output device (11) including a loudspeaker (10) and a transmitter for transmitting the second signal in analog form to the loudspeaker (10), characterized in that it further includes a control device (2) connected to the modulator (1) and receiving the signal from it and to the output device (11), the control device is adapted to control the output device (11) from a portion-of said predetermined period, and the length of said portion is determined as a function of the required volume.
摘要:
To reduce the DC-offset in bursts (B1, B2) of a digital signal (S1), some samples of one of the digital bursts (B1) which have no predetermined value are averaged by an averager (AV) resulting in a correction value (CV). Meanwhile the samples of this digital burst (B1) are temporarily stored in a memory (MEM1). The DC-offset correction value (CV) calculated by the averager (AV) is then substracted from the samples of the digital bursts (B1, B2). In this way, the dynamic range of the samples is reduced significantly.
摘要:
A differential current mode amplifier device generates a common mode bias current. A translinear multiplier receives at two inputs this common mode bias current and a differential mode current to be amplified and delivers at two outputs an amplified differential mode current. The translinear multiplier is biased in a manner depending on the bias current received by the translinear multiplier. The device includes a circuit for compensating the common mode current at the output of the translinear multiplier.
摘要:
A current-mode amplification system including a first gain section and at least one second gain section chained together to form a chain of gain sections. The first gain section containing a first amplifier and a first low-pass filter. Each second gain section contains: a second amplifier having (1) a first input receiving the amplified and filtered output current from the preceding gain section in the chain, and (2) a second input receiving an input current of the amplification system, and delivering an amplified output current; an activator/deactivator for activating/deactivating the second input; and a second low-pass filter, the low-pass filter of each of the chained-together gain sections having a high cut-off frequency, the high cut-off frequencies of the various gain sections increasing from the input to the output of the amplification system.