Apparatus for generating time code signal

• US 6,222,980 B1
• Filed: 03/25/1998
• Issued: 04/24/2001
• Est. Priority Date: 03/27/1997
• Status: Expired due to Term

• Current Assignee: Rakuten, Inc. (Rakuten Group, Inc.)
• Original Assignee: Victor Company of Japan Limited (JVC Kenwood Corporation)
• Inventors: Ishiwata, Masaki, Asai, Hiroshi
• Primary Examiner(s): Chevalier, Robert
• Application Number:
  US09/047,374
• Time in Patent Office: 1,126 Days
• Field of Search: H04/N.5782, H04/N.57822, 386/65, 386/61, 386/62, 386/57, 386/59, 386/52, 386/66, 386/46, 386/1, 386/4, 386/60, 360/72.1, 360/72.2, 360/72.3, 360/13, 360/69, 360/27, 360/49
• US Class Current: 386/207
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22
• CPC Class Codes: G11B 27/024 on tapes G11B27/028, G11B27/029 take precedence
• CPC Class Codes: G11B 27/028 with computer assistance
• CPC Class Codes: G11B 27/323 Time code signal, e.g. on a cue track as SMPTE- or EBU-time code
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus

Abstract

A direction detector operates for detecting a direction of feed of a recording tape. A timer operates for counting pulses of a clock signal, and outputting a signal representing a first count value. A second count value is generated which corresponds to a pulse width related to a first bit represented by an input time code signal reproduced from the recording tape. The first count value which occurs at a first time point and the second count value are added into a first addition-result value. An output time code signal is inverted when the first count value currently represented by the output signal of the timer comes equal to the first addition-result value. A second bit is selected from among bits represented by the input time code signal in response to the direction detected by the direction detector. The second bit to be selected neighbors the first bit in a normal time direction when the detected direction agrees with a forward direction. The second bit to be selected neighbors the first bit in a reverse time direction when the detected direction agrees with a reverse direction. A third count value is generated which corresponds to a pulse width related to the second bit. The first count value which occurs at a second time point after the first time point and the third count value are added into a second addition-result value. The first addition-result value is updated into the second addition-result value.

Claims

1. A time code signal generating apparatus comprising:

a direction detector for detecting a direction of feed of a recording tape;

a timer for counting pulses of a clock signal, and outputting a signal representing a first count value corresponding to a number of counted pulses;

first means for generating a second count value corresponding to a pulse width related to a first bit represented by an input time code signal reproduced from the recording tape;

second means for adding the first count value represented by the output signal of the timer at a first time point and the second count value generated by the first means into a first addition-result value;

third means for comparing the first addition-result value generated by the second means and the first count value currently represented by the output signal of the timer to detect that the first count value currently represented by the output signal of the timer comes equal to the first addition-result value generated by the second means;

fourth means for generating an output time code signal;

fifth means for inverting the output time code signal generated by the fourth means when the third means detects that the first count value currently represented by the output signal of the timer comes equal to the first addition-result value generated by the second means;

sixth means for selecting a second bit from among bits represented by the input time code signal in response to the direction detected by the direction detector, wherein the second bit to be selected neighbors the first bit in a normal time direction when the direction detected by the direction detector agrees with a forward direction, and the second bit to be selected neighbors the first bit in a reverse time direction when the direction detected by the direction detector agrees with a reverse direction;

seventh means for generating a third count value corresponding to a pulse width related to the second bit selected by the sixth means;

eighth means for adding the first count value represented by the output signal of the timer at a second time point after the first time point and the third count value generated by the seventh means into a second addition-result value; and

ninth means for updating the first addition-result value used by the third means into the second addition-result value generated by the eighth means.

2. A time code signal generating apparatus as recited in claim 1, wherein the input time code signal is recorded on the recording tape in synchronism with every frame represented by a video signal recorded on the recording tape.

3. A time code signal reading apparatus comprising:

an edge detector for detecting every rising edge and every falling edge in an input time code signal, and generating an edge detection signal representative thereof;

first means for detecting pulse widths of the input time code signal in response to the edge detection signal generated by the edge detector;

second means for deciding logic states of bits in response to the pulse widths detected by the first means;

third means for generating an active error flag when the pulse widths detected by the first means are arranged in an abnormal order;

fourth means for detecting a sync word represented by the bits in the logic states decided by the second means;

fifth means for deciding whether or not the sync word detected by the fourth means has a predetermined pattern, and generating a pattern decision signal representative thereof;

sixth means for recovers a first time value from the bits in the logic states decided by the second means; and

seventh means for correcting the first time value recovered by the sixth means into a second time value in response to the active error flag generated by the third means and the pattern decision signal generated by the fifth means.

4. A time code signal reading apparatus as recited in claim 3, wherein the seventh means comprises:

eighth means for changing the first time value by a given value to convert the first time value to a third time value;

ninth means for setting a seriality comparison value equal to the third time value generated by the eighth means;

tenth means for changing the second time value by a predetermined value to update the second time value;

eleventh means for, in cases where the active error flag is absent and the pattern decision signal represents that the sync word has the predetermined pattern, comparing the first time value with the seriality comparison value set by the ninth means at a previous moment to decide whether the first time value is equal to or different from the seriality comparison value set by the ninth means at the previous moment;

twelfth means for enabling the eighth means, the ninth means, and the tenth means to operate when the eleventh means decides that the first time value is different from the seriality comparison value set by the ninth means at the previous moment;

thirteenth means for changing the first time value by the given value to convert the first time value to the third time value when the eleventh means decides that the first time value is equal to the seriality comparison value set by the ninth means at the previous moment;

fourteenth means for setting the seriality comparison value equal to the third time value generated by the thirteenth means; and

fifteenth means for setting the second time value equal to the seriality comparison value set by the fourteenth means to update the second time value when the eleventh means decides that the first time value is equal to the seriality comparison value set by the ninth means at the previous moment.

5. A time code signal reading apparatus as recited in claim 4, further comprising a direction detector for detecting a direction of feed of a recording tape from which the input time code signal is reproduced, and wherein the eighth means increments the first time value by the given value when the direction detected by the direction detector agrees with a forward direction, and decrements the first time value by the given value when the direction detected by the direction detector agrees with a reverse direction, wherein the tenth means increments the second time value by the predetermined value when the direction detected by the direction detector agrees with the forward direction, and decrements the second time value by the predetermined value when the direction detected by the direction detector agrees with the reverse direction, and wherein the thirteenth means increments the first time value by the given value when the direction detected by the direction detector agrees with the forward direction, and decrements the first time value by the given value when the direction detected by the direction detector agrees with the reverse direction.

6. A time code signal rearranging apparatus comprising:

a bi-phase demodulator for subjecting a first time code signal reproduced from a magnetic tape to bi-phase demodulation to convert the first time code signal into a first sequence of time code bits;

a direction detector for detecting a direction of feed of the magnetic tape;

first means for dividing the first sequence of time code bits into segments each having a given number of time code bits;

second means for, when the direction detected by the direction detector agrees with a reverse direction, reversing an arrangement order of time code bits in each of the segments generated by the first means to rearrange the first sequence of time code bits into a second sequence of time code bits; and

a bi-phase modulator for subjecting the second sequence of time code bits generated by the second means to bi-phase modulation to convert the second sequence of time code bits into a second time code signal.