Beat frequency oscillator type 1022 serial no. 125809, made in Denmark by Bruel & Kjaer, Copenhagen, range 20Hz to 20kHz Beat frequency oscillator type 1022 serial no. 125809 1960-1979
Beat frequency oscillator, Bruel & Kjaer, Copenhagen, Denmark, model 1014, in fitted carrying case, serial no.22663, circa 1955, with 2 leads (loose) Beat frequency oscillator circa 1955