Doubly balanced mixer with optimized dynamic range
US4230956A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 15, 1978 |
| Grant date | Oct 28, 1980 |
| Priority date | — |
| Expiry date | May 15, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D7/1408
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit for mixing first and second rf signals to produce an output signal containing a beat frequency comprises a pair of switches each of which has a four diode bridge controlled by the first rf signal. The first rf signal is coupled to a balanced current divider with common mode signal rejection. Load resistors coupled to the bridges provide matched termination of the first rf signal irrespective of the conductive state of the bridges. The value of the resistors and the characteristic impedance of the drive circuit is related to the characteristics of the diodes utilized to maximize the dynamic range of the mixer. Circuitry is provided for coupling all diodes of each bridge in series with respect to the average dc component of the first rf signal and to properly terminate the average dc component. The two diode bridges are conductive and non-conductive in opposing half cycles of the first rf signal. A hybrid has its summing port coupled to the switch port of one bridge and its difference port coupled to the switch port of the other bridge. The second rf signal is coupled to input port of the hybrid which includes a balun for balancing and rejecting common mode signals from the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.