Integrated circuit

Abstract: An integrated circuit (2) includes a drum phase detection signal generating unit (2A) formed by two-stage amplifiers (20, 21) and a comparator (22), a drum frequency detection signal generating unit (2B) similarly formed by two-stage amplifiers (23, 24) and a comparator (25), a capstan frequency detection signal generating unit (2C), a supply reel frequency detection signal generating unit (2D) and a take-up frequency detection signal generating unit (2E) each formed by a comparator (26 to 27). From respective associated voltage sources a predetermined voltage is applied to each of the first stage amplifiers (20, 23), second stage amplifiers (21, 24), and comparators (22, 25 to 28) of the drum phase detection signal generating unit (2A), the drum frequency detection signal generating unit (2B), the capstan frequency detection signal generating unit (2C), the supply reel frequency detection signal generating unit (2D), and the take-up reel frequency detection signal generating unit (2E).

Description: This invention relates to integrated circuits which may, for example, be applied to a rotary head digital audio tape recorder to generate various sensor detection signals. In a rotary head digital audio tape recorder (R-DAT), audio data are recorded and/or reproduced on or from a magnetic tape wound around a rotary head. The recording/reproducing timing of the rotary head, the relative speed between the rotary head and the magnetic tape, and rotary head tracking or the tape running speed, are controlled using sensor output signals obtained from sensors provided in the rotary drum carrying the rotary head, and from a capstan and supply and take-up reels for the magnetic tape. More specifically, the rotary drum includes a drum phase sensor formed by small magnets secured to the outer periphery of the drum, a magnetic head for detecting the passage of the magnets, and a drum frequency sensor. The drum phase signal and the drum frequency signal, obtained as output signals from the associated sensors, are supplied to the downstream side drum phase detection signal generating circuit and drum frequency detection signal generating circuit, respectively. The capstan and the magnetic tape supply and take-up reels are provided with a capstan frequency sensor, a supply reel frequency sensor, and a take-up reel frequency sensor, respectively. The capstan frequency signal, supply reel frequency signal, and the take-up reel frequency signal, obtained from these sensors, are transmitted to a capstan frequency detection signal generating circuit, a supply reel frequency detection signal generating circuit, and a take-up reel frequency detection signal generating circuit, respectively. The drum phase detection signal generating circuit, the drum frequency detection signal generating circuit, the capstan frequency detection signal generating circuit, the supply reel frequency detection signal generating circuit, and the take-up reel frequency detection signal generating circuit are such that the input sensor signals are amplified and converted into binary signals with a predetermined threshold level as the boundary; and the drum phase detection and drum frequency detection signal, the capstan frequency detection signal, the supply reel frequency detection signal, and the take-up reel frequency detection signal are transmitted to a drum servo circuit, a capstan servo circuit, and supply and take-up reel motor control circuits, respectively. In this R-DAT, the circuit configuration could be simplified if the five sensor detection signal generating circuits could be formed on one integrated circuit. However, with the drum phase detection signal generating circuit and the drum frequency detection signal generating circuit, the input frequencies are low, that is tens to hundreds of kilohertz, while the input signals are of small amplitudes, that is tens of or less microvolts and hundreds of or less microvolts, respectively. Thus, an amplifier of an extremely high gain is required to produce detection signals in the form of 0 to 5 volts digital signals. On the other hand, the capstan frequency detection signal generating circuit generates a signal of a large amplitude with an input level of several to tens of millivolts, whereas the supply reel frequency detection signal generating circuit and the take-up reel frequency detection signal generating circuit generate signals of large amplitudes with an input current of not less than 30 microamperes, so that they are each formed by an amplifier with a broader operating margin. Hence, if these five sensor detection signal generating circuits are simply formed on an integrated circuit, the large amplitude input signals to the supply reel frequency detection signal generating circuit and to the take-up reel frequency detection signal generating circuit may occasionally leak into the drum phase detection signal generating circuit or into the drum frequency detection signal generating circuit and give rise to oscillations or the like which interfere with the smooth and stable operation of the integrated circuit. According to the present invention there is provided an integrated circuit for generating predetermined sensor detection signals in a recording and/or reproducing apparatus for recording and/or reproducing predetermined information data on or from a tape-shaped recording medium wound on a rotary head, the integrated circuit comprising: drum phase detection signal generating means including first and second amplifier circuit means connected in series for amplifying a drum phase signal obtained from said rotary head, and a first comparator means for generating a drum phase detection signal from the amplified drum phase signal; drum frequency detection signal generating means including third and fourth amplifier means connected in series for amplifying a drum frequency signal produced by said rotary head, and a second comparator means for generating a drum frequency detection signal from the amplified drum frequency signal; capstan frequency signal generating means including a third comparator means for generating a capstan frequency detection signal from a capstan frequency signal produced by a capstan motor driving said tape-shaped recording medium; supply reel frequency detection signal generating means including a fourth comparator means for generating a supply reel frequency detection signal from a supply reel frequency signal obtained from a supply reel of said tape-shaped recording means; take-up reel frequency detection signal generating means including a fifth comparator means for generating a take-up reel frequency detection signal from a take-up reel frequency signal obtained from a take-up reel of said tape-shaped recording medium; and a first independent power source means for supplying power to said first and third amplifier circuit means, a second independent power source means for supplying power to said second and fourth amplifier circuit means, and a third independent power source means for supplying power to said first to fifth comparator means. An embodiment of the present invention provides an integrated circuit for generating predetermined sensor detection signals in a recording/reproducing apparatus for recording and/or reproducing predetermined information data on a tape-shaped recording medium wound around a rotary head drum. The integrated circuit comprises a drum phase detection signal generating means formed by first and second amplifiers for amplifying drum phase signals obtained from a rotary head. A first comparator generates a drum phase detection signal from the amplifier drum phase signal. A drum frequency detection signal generating means is formed by third and fourth amplifiers for amplifying the drum frequency signal obtained from the rotary head. A second comparator generates the drum frequency detection signal from the amplified drum frequency signal. A capstan frequency detection signal generating means is formed by a third comparator for generating the capstan frequency detection signal from the capstan frequency signal obtained from the capstan which drives the tape-shaped recording medium. A supply reel frequency detection signal generating means is formed by a fourth comparator for generating the supply reel frequency detection signal from the supply reel frequency signal obtained from the supply reel for the tape-shaped recording medium. A take-up reel frequency detection signal generating means is formed by a fifth comparator for generating the take-up reel frequency signal obtained from the take-up reel for the tape-shaped recording medium. First, second and third power source means are provided for supplying a predetermined voltage to the first and third amplifiers, to the second and fourth amplifiers, and to the first to fifth comparators. With the above described integrated circuit, there are provided drum phase detection signal generating means formed by two-stage amplifiers and a comparator. A drum frequency detection signal generating means is likewise formed by two-stage amplifiers and a comparator. A capstan frequency detection signal generating means, a supply reel frequency detection signal generating means, and a take-up reel frequency detection signal generating means are each formed by a comparator. A predetermined voltage is supplied to each of a group of the first stage amplifiers, a group of the second stage amplifiers, and a group of the comparators to prevent the large amplitude input signals to the capstan frequency detection signal generating means, to the supply reel frequency detection signal generating means, or to the take-up reel frequency detection signal generating means from being inadvertently input into the drum phase detection signal generating means or into the drum frequency detection signal generating means by way of the voltage sources. In this manner, the drum phase detection signal generating means, the drum frequency detection signal generating means, the capstan frequency detection signal generating means, the supply reel frequency detection signal generating means, and the take-up reel frequency detection signal generating means can be formed in one integrated circuit and operated with improved stability. The sole figure is a circuit diagram showing a portion of a rotary head digital audio tape recorder employing an integrated circuit according to the present invention. In the figure, a rotary head type digital audio tape recorder (R-DAT) 1 employing an integrated circuit 2 according to the present invention is shown. The R-DAT 1 employs a DAT cassette 3. A magnetic tape 5 is extracted from a supply reel is within the bAT cassette 3 and is wound through an angle of 180° on a drum 9 by means of two guide pins 6 and 7 so as to be then taken up on a take-up reel 12 within the cassette 3 by means of a capstan 10 and a pinch roll 11 driving the tape 5. Rotary heads 8A and 8B formed by a pair of magnetic heads angularly spaced by about 180° from each other are mounted on the drum 9. With the R-DAT 1, a drum phase sensor is formed by a small magnet 13 secured to the other periphery of the drum 9 and a magnetic head 14 provided at a predetermined position near the perimeter of the drum 9. As the small magnet 13 passes the magnetic head 14 in response to rotation of the drum 9, a drum phase signal S PGDR which rises and falls in the form of a sinusoidal wave for each rotation of the drum 9 is obtained as the output signal of the drum phase sensor. This drum phase signal is input at an input terminal a of a drum phase detection signal generating section 2A of the integrated circuit 2. A drum motor rotating the drum 9, a capstan motor rotating the capstan 10, and a reel motor rotating the supply reel 4 and the take-up reel 12 are provided with respective frequency sensors, each of frequency generator configuration. A drum frequency signal S FGDR , a capstan frequency signal S FGCP , a supply reel frequency signal S FGSP , and a take-up reel frequency signal S FGTU , obtained as sensor output signals as a result of rotations of the associated components, are input at input terminals b , c , d , and e of a drum frequency detection signal generating section 2B, a capstan frequency detection signal generating section 2C, a supply reel frequency detection signal generating section 2D, and a take-up reel frequency detection signal generating section 2E of the integrated circuit 2, respectively. In practice, the drum phase detection signal generating section 2A is formed by two-stage amplifiers 20 and 21, each in the form of an operational amplifier, and a comparator 22, and is so arranged and constructed that the input drum phase signal S PGDR is amplified to a predetermined level and compared with a predetermined threshold level. The resulting comparison signal is converted into a binary signal to produce a drum phase detection signal PG DR which rises and falls a predetermined number of times for each revolution of the drum 9. This drum phase detection signal is output at an output terminal f . Similarly to the drum phase detection signal generating section 2A, the drum frequency detection signal generating section 2B is formed by two-stage amplifiers 23 and 24, each in the form of an operational amplifier, and a comparator 25, and is so arranged and constructed that the input drum frequency signal S FGDR is amplified to a predetermined level and compared with a predetermined threshold level. The resulting comparison signal is converted into binary signals to produce a drum frequency detection signal FG DR which rises and falls at the repetitive frequency related to the rotation of the drum 9. This drum frequency detection signal FG DR is output at an output terminal g . The capstan frequency detection signal generating section 2C is formed by a comparator 26 in the form of an operational amplifier and so arranged and constructed that the input capstan frequency signal S FGCP is compared with a predetermined threshold level and converted into a binary signal to produce a capstan frequency detection signal FG CP which rises and falls at the repetitive frequency related to the rotation of the capstan 10. This capstan frequency detection signal FG CP is output at an output terminal h . The supply reel frequency detection signal generator 2D and the take-up reel frequency detection signal generator 2E are also formed by comparators 27 and 28, each in the form of an operational amplifier, and so arranged and constructed that the input supply reel frequency signal S FGSP and the input take-up reel frequency signal S FGTU are compared with predetermined threshold levels and converted into respective binary signals. The resulting supply reel frequency detection signal FG SP and take-up reel frequency detection signal FG TU rising and falling at the repetitive frequency related to rotation of the supply reel 4 and the take-up reel 12, respectively, are generated and output at output terminals i and j , respectively. With the integrated circuit 2, a first voltage V CC1 obtained from a first voltage source line on the integrated circuit pattern is input to an internal regulating section 29 to produce a stabilized voltage V CC0 which is supplied to the first stage amplifier 20 of the drum phase detection signal generating section 2A and to the first stage amplifier 2B. The amplifiers 20 and 23 are grounded to a first grounding line GND₀ on the integrated circuit pattern. The first voltage V CC1 is also supplied to the second stage amplifiers 21 and 24 of the drum phase detection signal generating sections 2A and the drum frequency detection signal generating sections 2B, respectively. These second stage amplifiers 21 and 24 are grounded at a second grounding line GND1 on the integrated circuit pattern. A second voltage V CC2 from a second voltage source line on the integrated circuit pattern is supplied to the comparators 22, 25, 26, 27 and 28 in the drum phase detection signal generating section 2A, the drum frequency detection signal generating section 2B, the capstan frequency detection signal generating section 2C, the supply reel frequency detection signal generating section 2D, and the take-up reel frequency detection signal generating section 2E. The comparator circuit 22, 25, 26, 27 and 28 are also grounded at a third grounding line GND2 on the integrated circuit pattern. In this manner, with the integrated circuit 2, the comparators 22, 25, 26, 27 and 28 of the drum phase detection signal generating section 2A, the drum frequency detection signal generating section 2B, the capstan frequency detection signal generating section 2C, the supply reel frequency detection signal generating section 2D, and the take-up reel frequency detection signal generating section 2E, respectively, the first and second stage amplifiers 20, 23, 21, 24 of the drum phase detection signal generating section 2A, and the drum frequency detection signal generating section 2B are connected to the different voltage lines V CC0 , V CC1 and V CC2 and to the different grounding lines GND0, GND1 and GND2 on the integrated circuit pattern. In this manner, the large amplitude input signal formed by the capstan frequency signal S FGCP , the supply reel frequency signal S FGSP , and the take-up reel frequency signal S FGTU input to the capstan frequency detection signal generating section 2C, the supply reel frequency detection signal generating section 20, and the take-up reel frequency detection signal generating section 2E are prevented from being mixed with input signals to the drum phase detection signal generating section 2A or the drum frequency detection signal generating section 2B via the voltage lines V CC0 , V CC1 and V CC2 and/or the grounding lines GND0, GND1 and GND2. Thus the drum phase detection signal generating section 2A, the drum frequency detection signal generating section 2B, the capstan frequency detection signal generating section 2C, the supply reel frequency detection signal generating section 2D, and the take-up reel frequency detection signal generating section 2E formed on the single integrated circuit can be operated separately and with stability. With the integrated circuit 2, the drum phase detection circuit 2A formed by the two-stage amplifiers 20 and 21 and the comparator 22, the drum frequency detection signal generating section 2B formed by the two-stage amplifiers 23 and 24 and the comparator 25, the capstan frequency detection signal generating section 2C, the supply reel frequency detection signal generating section 2D, and the take-up reel frequency detection signal generating section 2E formed by the comparators 26, 27 and 28, are formed in one integrated circuit. The predetermined voltages V CC0 , V CC1 and V CC2 are supplied to the first stage amplifiers 20 and 23; to the second stage amplifiers 21 and 24; and to the comparators 22, 25, 26, 27 and 28, respectively, to prevent the large amplitude input signals formed by the capstan frequency signal S FGCP , the supply reel frequency signal S FGSP and the take-up reel frequency signal S FGTU from mixing in with input signals to the sections 2A or 2B via the voltage lines or the grounding lines. Thus the integrated circuit 2 of simplified construction may be realized in which the drum phase detection signal generating section 2A, the drum frequency detection signal generating section 2B, the capstan frequency detection signal generating section 2C, the supply reel frequency detection signal generating section 2D, and the take-up reel frequency detection signal generating section 2E are provided on one circuit chip and are operable with stability. Although the drum phase detection signal generating section and the drum frequency detection signal generating section are each formed by two stage amplifiers and a comparator in the above embodiment, effects similar to those of the above embodiment may be realized by proper allocation of the power source lines, even in cases wherein for example a wave-forming circuit or a like circuit device is provided between the two amplifier stages or between the second stage amplifier and the comparator. In addition, although the capstan frequency detection signal generating section, the supply reel frequency detection signal generating section, and the take-up reel frequency detection signal generating section and formed by respective comparators, effects similar to those of the above embodiment may be realized by proper allocation of the voltages lines even in those cases wherein amplifiers or like circuit elements are provided ahead and/or following the comparators. Moreover, although the foregoing description is of the case in which the present invention is applied to an R-DAT, it may be applied to an integrated circuit employed in another recording/reproducing apparatus for recording and/or reproducing data on or from a recording medium in the form of a tape wound on a rotary head, such as a video tape recorder.

Claims: An integrated circuit (2) for generating predetermined sensor detection signals in a recording and/or reproducing apparatus (1) for recording and/or reproducing predetermined information data on or from a tape-shaped recording medium (5) wound on a rotary head (8A, 8B), the integrated circuit (2) comprising: drum phase detection signal generating means (2A,) including first and second amplifier circuit means (20, 21) connected in series for amplifying a drum phase signal obtained from said rotary head (8A, 8B), and a first comparator means (22) for generating a drum phase detection signal from the amplified drum phase signal; drum frequency detection signal generating means (2B) including third and fourth amplifier means (23, 24) connected in series for amplifying a drum frequency signal produced by said rotary head (8A, 8B), and a second comparator means (25) for generating a drum frequency detection signal from the amplified drum frequency signal; capstan frequency signal generating means (2C) including a third comparator means (26) for generating a capstan frequency detection signal from a capstan frequency signal produced by a capstan motor driving said tape-shaped recording medium (5); supply reel frequency detection signal generating means (2D) including a fourth comparator means (27) for generating a supply reel frequency detection signal from a supply reel frequency signal obtained from a supply reel (4) of said tape-shaped recording means (5); take-up reel frequency detection signal generating means (2E) including a fifth comparator means (28) for generating a take-up reel frequency detection signal from a take-up reel frequency signal obtained from a take-up reel (12) of said tape-shaped recording medium (5); and a first independent power source means (29) for supplying power to said first and third amplifier circuit means (20, 23), a second independent power source means for supplying power to said second and fourth amplifier circuit means (21, 24), and a third independent power source means for supplying power to said first to fifth comparator means (22, 25 to 28). A circuit (2) according to claim 1, wherein said first independent power source means is formed by an internal regulating section means (29) for producing a stabilized voltage. A circuit (2) according to claim 1 or 2, wherein said first and third amplifier means (20, 23) are connected to a first grounding line, the second and fourth amplifier means (21, 24) are connected to a second grounding line which is independent of the first grounding line, and said first to fifth comparator means (22, 25 to 28) are connected to a third grounding line which is independent of the first and second grounding lines. A circuit (2) according to any preceding claim, wherein the drum phase signal and the drum frequency signal produced by said rotary head (8A, 8B) have voltage levels which are in a microvolt range and are substantially smaller than voltage levels of said capstan frequency signal, supply frequency signal, and take-up reel frequency signal in a millivolt range.

Inventors: FUKUDA SHINICHI C O PATENTS DI, FUKUDA, SHINICHI, C/O PATENTS DIVISION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1990
Main classification: G11B15
IPC codes: G11B15