Two auxiliary heads are provided in addition to the two main heads for a helical scan video signal tape recorder. The vertical and horizontal positions of the auxiliary heads are determined so as to effectively reproduce a slow-motion picture from a magnetic tape on which the signals are recorded using the so called "azimuth" recording method. The output of each head is selectively supplied to a video signal demodulating circuit via a switching circuit.
A reproduced signal switching circuit for a reproducing apparatus, comprises a switching circuit for switching output signals of rotary heads for special reproduction so as to obtain a continuous reproduced signal, a switching signal producing circuit for producing a switching signal responsive to an output pickup pulse of a rotation detecting circuit which detects the rotation of a rotary body which is mounted with the rotary heads, and for applying the switching signal to the switching circuit so as to switch the switching circuit, and a voltage supplying circuit for supplying a voltage which is in accordance with a tape moving speed to the switching signal producing circuit during the special reproduction. The switching signal producing circuit comprises time constant circuits for starting charging operations responsive to the pickup pulse, and a circuit for producing a switching signal having a polarity which changes when charged voltages in the time constant circuits reach a predetermined voltage. The voltage supplying circuit supplies the voltage to be charged to the time constant circuits.
A video signal recording/reproducing apparatus has two main rotary heads, two sub-rotary heads, and a recorded video tape. One main rotary head M1 has a +6.degree. azimuth angle and one sub-rotary head S1 has a -6.degree. azimuth angle. The sub-rotary head S1 is mounted near the main rotary head M1. For example, the distance between the main rotary head M1 and the sub-rotary head S1 corresponds to two horizontal sync signal intervals of a video signal. Main rotary head M2 has a -6.degree. azimuth angle and sub-rotary head S2 has a +6.degree. azimuth angle. The distance between the main rotary head M2 and the sub-rotary head S2 is the same as that between M1 and S1. The main rotary head M2 is located at a position opposite to the main rotary head M1 on a rotary head disk. In the fast motion reproduction mode, the main rotary head M1 and the sub-rotary head S1 scan recorded video tracks on the video tape. The reproduced signal of the main rotary head M1 has several lower or zero level positions in one field. The reproduced signal of the sub-rotary head S1 is selectively substituted for the lower or zero level positions of the reproduced signal of the main rotary head M1.
A rotary head type reproducing apparatus for reproducing information signals recorded in a plurality of recording tracks by tracing, with rotary type magnetic heads, the recording tracks which are formed on a tape-shaped magnetic record bearing medium in a direction of crossing the longitudinal direction of the medium comprises: pairs of magnetic heads which are positioned in the vicinity of each other with each pair of heads arranged to have different azimuth angles from each other; a rotary member arranged to have the pairs of magnetic heads mounted on the circumference thereof; rotation period detecting means arranged to detect the rotation period of the rotary member and to produce a rotation period information signal corresponding to the rotation period detected; and output selection means for selectively producing, according to the rotation period information signal, the information signals reproduced from the recordng tracks by the pairs of magnetic heads through their tracing action on the tape-shaped magnetic record bearing medium.
Disclosed is a four-head image reproduction system for performing a slow motion video reproduction in the forward and reverse directions by intermittently repeating stoppage and normal speed operation of a magnetic tape on which images are recorded in accordance with the azimuth technique. In response to a reproduction control signal which has reference pulses of a predetermined polarity generated from a detecting section including a control head, a control section first receives the reference pulse regardless of the forward or reverse slow reproduction mode and then stops a capstan when a period of time corresponding to half the period of the reference pulse elapses. In this condition, the level of a pair of heads for special reproduction mounted on a rotating drum is set to have a predetermined difference from that of a pair of heads for normal recording/reproducing.
A multichannel recorder, such as for color video, reduces the width of recording heads that record low frequencies, and interchanges the order of one such head with a high frequency head. This both reduces crosstalk and keeps interchannel time displacement low.
