High dynamic range mixer

2 high dynamic range mixer to80kHz;thirdharmonicdistortion of not m ore than 0.05 per cent at 10kHzandanoutputvoltageof 9Vpp;andasignal-to-noiseratioof 100dB. Thesignal-to-noiseratioappliestoan outputsignalof9Vppwithopen- circuitinput,and a bandwidth of 20kHz.Themaximum valueofthe outputsignalisabout12Vpp, measured across a load impedance of560ohms.Ifthemixerister- minatedbyahigherimpedance,the output voltage will be greater. Afurtheradvantageofthecircuitis thatthepopularvalvesoundmaybe Amixerisexpectedtohavelow- theconstructingofoperational noise and high dynam ic perform - am plifiers from good-quality tran- ance.Moststandardmixersusein- sistors.Thishasbeendoneintheac- vertingoperationalamplifiers. Unfortunately,thenoisefigureof manyopampsispoor,andopamps withagoodnoisefigurearenormally not suitable for operating with large signals. Thenoisefactorofstandardcircuits is often made even poorer because the source and am plifier are not properly matched. The characteristics of a mixe...