Abstract: An apparatus is provided for recording on videotape to insure the absence phase error between different sequences in the assembling mode. The apparatus includes a reference pulse source and circuitry to apply reference pulses from the source to a first recording of the tape through a fixed transducer head for recording and playback. The reference pulses also control the speed of the motor driving the tape through a servo mechanism. A tachometer-generator is operatively connected to the motor to produce a train of pulses related to the motor speed at a frequency comprising a fixed integer multiple of the frequency of the reference pulses. The output of the tachometer is fed to a counter which divides the tachometer pulses by the fixed integer so that the output of the counter represents a train of pulses, the frequency of which is equal to that of the reference pulses.

Abstract: Received signal is filtered by a filter tuned to a predetermined harmonic the modulation frequency lying outside of the modulation region of the received signal. Such harmonic results from modulation distortion due to multipath reception. Output of filter is irregularly occurring pulse sequence which is converted to a constant signal which in turn energizes an indicator.