公开(公告)号：EP1057254A1

公开(公告)日：2000-12-06

申请号：EP99963089.0

申请日：1999-12-15

申请人： Raytheon Company

发明人： SPARGO, Thomas, A. ,  LINDER, Lloyd, F. ,  GORDER, Matthew, S.

IPC分类号： H03D7/16

CPC分类号： H03D3/007

摘要： A system and method for effecting wideband image rejection. In a receiver implementation, the inventive method includes the steps of receiving a first signal in a first frequency band and generating in-phase and quadrature signals therefrom. The phase of the in-phase signal is shifted to provide a second signal and the phase of the quadrature signal is shifted to provide a third signal. A predetermined phase relationship is thereby effected between the second and the third signals. The second and third signals are then summed to provide an output signal which has minimal interference from a mixing signal. In an illustrative receiver application, the phase shifting is achieved via the use of all pass networks. Each of the all pass networks include a differential amplifier having first and second input terminals. The first and the second terminals are connected to a first end of first and second resistive elements, respectively. The second ends of the first and second resistive elements are connected to a common input terminal for the network. The first input terminal is a negative terminal and is connected to an output terminal of the network. The second terminal is a positive terminal and is connected to a source of ground potential via a capacitive element.

公开(公告)号：EP0909479A1

公开(公告)日：1999-04-21

申请号：EP98920924.0

申请日：1998-04-30

申请人： Raytheon Company

发明人： CHEN, Ricky, Y. ,  LINDER, Lloyd, F. ,  DEVENDORF, Don, C. ,  GORDER, Matthew, S.

IPC分类号： H03G3 ,  H03D7 ,  H03G1

CPC分类号： H03G1/0023 ,  H03D7/1408 ,  H03D7/1433 ,  H03D7/1441 ,  H03D7/1458 ,  H03D7/1491 ,  H03D2200/0025 ,  H03D2200/0047

摘要： A 'gain control differential pair' (GCDP) (10) conducts current in response to a differential drive signal, with the gain of a signal path formed via the current circuit of one of its transistors controlled by the drive signal. The GCDP is preferably driven with a drive circuit (20) that receives a symmetrical input signal and produces an offset differential drive signal which has the effect of keeping one of the GCDP's transistors turned off over a wider portion of a symmetrical input signal's voltage range, thereby reducing GCDP-caused noise. One or more GCDPs are implemented as part of a Gilbert mixer (30) to regulate the amount of RF current that flows between the mixer's output and input stages, which eliminates the need to provide gain control in other circuits fed by the mixer. When driven with an offset drive signal, the Gilbert mixer simultaneously provides gain control, low distortion, low power consumption and excellent LO/RF isolation.