Methods of and apparatus for recording and reproducing analog signals

Claim 3

A method according to claim 1 wherein said heads (1A, 1B) are equally spaced rotary magnetic recording heads (1A, 1B) that define a scanning period corresponding to the period of rotation of said heads (1A, 1B) and provide a series of consecutively formed tracks (4A, 4B) on a magnetic tape (2) forming said recording medium (2).

Claim 4

A method according to claim 2 wherein said analog signal is provided in two separate channels simultaneously and wherein said digital signal comprises a pulse code modulated (PCM) signal representing both of the channels of said anglog signal, and said additional data comprises parity data and a cyclic redundancy check code.

Claim 5

A method according to claim 3 wherein data corresponding to said separate channels are recorded in respective alternating tracks (4A, 4B).

Claim 6

A method of reproducing an analog signal which has been recorded by a method according to claim 1, and in which said additional data comprises an error correction code, the method comprising the steps of: periodically tracing the magnetic medium (2) with two reproducing heads (1A, 1B) in successive scanning periods during each of which both said reproducing heads (1A, 1B) scan said recording medium (2) once to provide two reproducing periods during each scanning period in which said recorded digital signal is reproduced from said recording medium (2), and two free periods during each scanning period in each of which both said reproducing heads (1A, 1B) are free of said recording medium (2); correcting any errors in said reproduced digital signal by means of the respective error correction code during said free periods; time-base expanding said corrected digital signal for reproducing said digital signal; and converting said digital signal into the corresponding analog signal.

Claim 7

A method according to claim 5 further comprising concealing any uncorrected errors in said time-base expanded digital signal prior to converting said digital signal into the corresponding analog signal.

Claim 8

Apparatus for recording an analog signal on a magnetic recording medium (2) in the form of a digital signal comprises a rotary head assembly having two recording heads (1A, 1 B) that periodically and alternately trace said recording medium (2) thereby defining a first recording period each time a first of said two heads (1A, 1 B) scans said recording medium (2), respective first and second free periods separating said second and first recording periods and said first and second recording periods, and converting means (15) to convert said analog signal to a digital signal on a real-time basis; characterized by: first and second consecutive signal periods being defined such that each said first signal period comprises a said first free period and said first recording period following that first free period, and each said second signal period comprises a said second free period and said second recording period following that second free period; a first memory means (17) in which during each said first signal period a first portion of the digital signal is stored on a real-time basis; a second memory means (18) in which during each said second signal period a second portion of said digital signal is stored on a real-time basis; means (25) to add, during each said first free period, second additional digital data to said digital signal stored in said second memory means (18) during the foregoing said second signal period, and to add, during each said second free period, first additional digital data to said digital signal stored in said first memory means (17) during the foregoing said first signal period; and means (27) operative, during each said first recording period, to time-compression read out said digital signal stored in said second memory means (18) and including said second additional digital data and to record said read out signal through said first head (1A) and, during each said second recording period, to time-compression read out said digital signal stored in said first memory means (17) and including said first additional digital data and to record said read out signal through said second head (1B).

Claim 9

Apparatus for recording an analog signal on a magnetic recording medium (2) in the form of a digital signal comprises a rotary head assembly having two recording heads (1A, 1 B) that periodically and alternately trace said recording medium (2) thereby defining a first recording period each time a first of said two heads (1A, 1 B) scans said recording medium (2), respective first and second free periods separating said second and first recording periods and said first and second recording periods, and converting means (15) to convert said analog signal to a digital signal on a real-time basis; characterized by: first and second consecutive signal periods being defined such that each said first signal period comprises a said first free period and said first recording period following that first free period, and each said second signal period comprises a said second free period and said second recording period following that second free period; a first memory means (17) in which during each said first signal period a first portion of the digital signal is stored on a real-time basis; a second memory means (18) in which during each said second signal period a second portion of said digital signal is stored on a real-time basis; means (25) to add, during each said first free period, second additional digital data to said digital signal stored in said second memory means (18) during the foregoing said second signal period, and to add, during each said second free period, first additional digital data to said digital signal stored in said first memory means (17) during the foregoing said first signal period; and means (27) operative, during each said first recording period, to time-compression read out said digital signal stored in said second memory means (18) and including said second additional digital data and to record said read out signal through said first head (1A) and, during each said second recording period, to time-compression read out said digital signal stored in said first memory means (17) and including said first additional digital data and to record said read out signal through said second head (1B).

Claim 10

Apparatus according to claim 7 wherein: said two heads (1A, 1B) are rotary and equally spaced to provide a series of consecutively formed tracks (4A, 4B) on said recording medium (2) which is in the form of a magnetic tape (2); and guide means (3) guides said tape (2) past said heads (1A, 1B) through an angular range substantially equal to 90°.

Claim 11

Apparatus according to claim 8 wherein: said two heads (1A, 1B) record an analog signal provided in two separate channels; said converting means (15) provides a pulse code modulated (PCM) signal representing both of the channels of the analog signal; and said additional digital data comprises parity data and a cyclic redundancy check code.

Claim 12

Apparatus according to claim 9 wherein said first and second memory means (17,18) comprise a pair of random-access memories (17, 18).