摘要:
The invention relates to a wideband phase shift device. A phase shift φ is introduced on the fixed frequency local oscillator. The principle of the invention is to realise a double translation of the input signals. The phase variation introduced at the level of the local oscillator has a positive value on one of the translated signals and a negative value on the other. The signals are recombined at the reception frequency with a phase difference of 2 φ so as to maximise the amplitude of the signal at the output of the summator.
摘要:
The reception device according to the invention enables, through a predictive detection of fading on the channels adjacent to the selected channel n, the phase of the incoming signals received from secondary antennas to be corrected so as to eliminate the fading.
摘要:
The present invention relates to a multiple-port dual-band antenna system and the associated interface formed by DPDT or SPDT switches, that can be integrated on one and the same multi-layer structure.
摘要:
The invention relates to a method of resending at least one digital signal, comprising a step of reception by cable of the signal comprising signaling information, a step of resending of this signal at a resend frequency by an antenna, and also comprising a step of selecting the resend frequency as a function of the signaling information; a step of transposing the signal into the selected frequency of the resend signal and a step of monitoring and adjusting the frequency of the resend signal as a function of the selected frequency of the resend signal.
摘要:
The invention concerns a system of antennas on the same support. Each antenna is connected to a first port for the emission/reception in a first frequency band, and to a second port for the emission/reception in a second frequency band. The invention consists in a specific dimensioning of the support, such that the difference of the perimetric lengths separating the median points is a function of the half wavelength λ/2 modulo k λ, k positive integer, where λ is the wavelength corresponding to a working frequency fr.
摘要:
This invention concerns a repeater for radio frequency signals.The repeater at least includes: a channel filter; an active filter connected to the channel filter output, covering the channels adjacent to the channel filter comprising: an amplifier the output of which forms the output of the said filter; two bandpass filters in parallel connected as a negative feedback loop around the amplifier, with a first bandpass filter covering the lower adjacent channels and a second bandpass filter covering the higher adjacent channels. The repeater can also include: a circuit converting the radio frequency signal into an intermediate frequency, with the channel filter filtering the signal converted into an intermediate frequency; a circuit converting the signal into an intermediate frequency at its original frequency. The invention notably applies to the development of domestic repeaters for mobile terminals meeting the DVB-H digital television standard.
摘要:
The present invention relates to a multiple-port dual-band antenna system and the associated interface formed by DPDT or SPDT switches, that can be integrated on one and the same multi-layer structure.
摘要:
The invention relates to a device for converting frequencies comprising a local oscillator of fixed frequency and a first mixer with two inputs and an output, a first input receiving the signal to be converted and a second input receiving the signal arising from the local oscillator. It further comprises a second mixer with two inputs and an output, a first input receiving the signal arising from the phase-shifted local oscillator and the second input receiving a dc signal whose value is dependent on the power of the residual spectral component at the output of an adder receiving as input the signals arising from the first and from the second mixer(s) and giving as output a transposed signal. The invention applies in particular in terminals operating in the Ka band.
摘要:
The invention relates to a switch with selective isolation and also to a switching device with selective isolation for multimedia terminals. The switch formed by 2 transistors (T1, T2) is feedback controlled by a feedback control signal V tune at a pre-defined frequency thus guaranteeing the selective isolation at this frequency. The switching device for switching the transmission/receiver channels of a multimedia terminal is formed by selective isolation switches that can be integrated using MMIC technology.
摘要:
The invention relates to processes and devices which make it possible to directly modulate an RF carrier with a quadrature signal. It consists in filtering (504) this quadrature signal around zero so as to introduce alternately (507, 508) on each of the channels a low-frequency subcarrier that will serve as reference. Each of these channels is alternately demodulated in a synchronous manner (519) cosine-wise and sine-wise. The demodulation signal is filtered (523) so as to recover the subcarrier marred by modulation errors. The measurement of these errors (524) allows feedback correction (503) of the quadrature signal. It makes it possible to perform the major part of the operations in the digital processor (501) and enables direct vector modulation to be made possible at millimeter frequencies.