公开(公告)号：EP0210688A3

公开(公告)日：1988-12-21

申请号：EP86201177

申请日：1986-07-04

申请人： PHILIPS ELECTRONIC AND ASSOCIATED INDUSTRIES LIMITED ,  N.V. Philips' Gloeilampenfabrieken

发明人： Marshall, Christopher Brian

IPC分类号： H03C01/00 ,  H03D01/00 ,  H04B01/68 ,  H04B07/12 ,  H04L05/26

CPC分类号： H04B7/12 ,  H03C1/00 ,  H03D1/00 ,  H04B1/68 ,  H04L5/26

摘要： A signal transmission system which is particularly suitable for the employment of direct conversion receivers has a block of adjacent transmission frequency bands allocated to it. Each signal channel is split into two sub-channels or parts occupying mutually different frequency bands for transmission and the bands occupied by the sub-channels of the various channels are interleaved. In the receiver the local oscillator is tuned midway between the bands corresponding to the sub-channels of the wanted channel and the corresponding signals are recovered by bandpass filtering, phase-shifting, summing and differencing, demodulating and combining the frequency down-converted outputs of quadrature related mixers to which the received and the local oscillator signals are applied. Although d.c. block capacitors are used in the outputs of the mixers, these can have a low value because the notch formed in the transmission frequency characteristic does not affect the reception of the required signals, so that the receiver can settle rapidly at switch-on.

公开(公告)号：EP0074858A3

公开(公告)日：1984-09-19

申请号：EP82304870

申请日：1982-09-15

申请人： International Standard Electric Corporation

发明人： Goatcher, John Kenneth

IPC分类号： H04B01/16 ,  H03D05/00 ,  H03D01/00 ,  H03D03/00 ,  H03D01/24

CPC分类号： H03D3/007 ,  H03D1/00 ,  H03D1/24 ,  H03D3/006 ,  H03D5/00 ,  H03D7/165 ,  H03D2200/0025 ,  H03D2200/0035 ,  H03D2200/005 ,  H03D2200/0052

摘要： A multi-mode radio receiver divides the radio frequency input into two channels and in each channel mixes it with the carrier wave frequency. A quadrature shift in the mixing carrier wave frequencies enables base band signals to be filtered from the mixer outputs. The analogue quadrature signals are converted to digital form and processed digitally to reproduce the original modulating signal for am, fm or pm transmissions. For ssb modulation the mixing frequency is the side band centre frequency instead of carrier frequency.

公开(公告)号：EP0099703A3

公开(公告)日：1985-06-19

申请号：EP83303973

申请日：1983-07-07

申请人： FUJITSU LIMITED

发明人： Miyo, Tokihiro

IPC分类号： H03D01/00

CPC分类号： H03D1/22 ,  H03D1/00

摘要： In an envelope detector, signal divider means (9) divide an input signal into a pair of output signals of equal amplitude and equal phase. A reference oscillator (5, 6) provides a pair of reference signals of equal amplitude of phases differing by 90°. In modulating means (7, 7') each output signal is modulated by a respective reference signal to provide modulated signals which are filtered by respective low pass filters (11, 11') to provide base band signals. The base band signals are squared by squaring circuits (12, 12') and the resulting signals added by an adder circuit (13). The square root of the sum may be provided by a square root circuit (14). Alternatively, the base band signals are delivered to absoluting circuits (15, 15') to provide their absolute values which are added in an adder circuit (13).

摘要翻译： 在包络检测器中，信号分配器装置（9）将输入信号划分成相等振幅和相等相位的一对输出信号。 参考振荡器（5,6）提供一对相位振幅相差90°的参考信号。 在调制装置（7,7分钟）中，每个输出信号被相应的参考信号调制以提供经相应低通滤波器（11,11分钟）滤波的调制信号，以提供基带信号。 基带信号由平方电路（12,12分钟）平方，并且由加法器电路（13）添加的结果信号。 总和的平方根可以由平方根电路（14）提供。 或者，将基带信号传送到绝对电路（15,15分钟），以提供其加在电路（13）中的绝对值。