Multitrack recorder including superimposed real time code

Abstract

A multitrack recorder is disclosed in which each of a plurality of parallel data signals is mixed with an additional signal corresponding to a digital code indicative of the real time at which the data is received. Each of the mixed signals is then conventionally recorded on a separate track of a suitable record medium. The recorder includes a circuit which shifts the phase of the recorded data signals with respect to each other, while keeping the phase of all recorded time signals in phase with each other. Upon playback, the signals from all tracks are added together. The out-of-phase data signals from each track tend to negate each other and the in-phase time related signals reinforce each other, thus becoming readily detectable. Preferably, the digital time related signals are encoded as two frequencies, both of which are below the band width of the data signals, such that frequency filters may also be employed to enhance the recovery of the time code.