MXPA00012328A - Track crossing discriminating circuit - Google Patents

Abstract

Out of the read signal an auxiliary signal (Sa) having a relatively low frequency content is generated. The apparatus comprises for the auxiliary signal (Sa) first hold means (8) for generating a first hold signal (H1) and second hold means (9) for generating a second hold signal (H2). The first hold means (8) are adapted for temporarily maintaining the value of the first hold signal (H1) at a value substantially corresponding to the bottom value of the auxiliary signal augmented by an addition value (Sa+&Dgr;) and the second hold means for temporarily maintaining the value of the second hold signal (H2) at a value corresponding to a top value of the auxiliary signal diminished by a subtraction value (Sa-&Dgr;).

Description

DISCRIMINATORY CIRCUIT OF ROAD CROSSING The invention in question is a device to control the transmission of records. Such a device has a transducer that generates a reading signal from the patterns registered by the record transmitter; It also has the necessary resources to change the relative position between the transducer and the record transmitter. The device in question has the necessary means to generate an auxiliary signal from the reading signal. Such an auxiliary signal has a relatively lower frequency than the read signal. The device has the means for generating binary signals from the auxiliary signal. The following elements are included here: the primary retention means and the generation of the respective signal; the secondary retention means and the generation of the respective signal; means for combining the signals and generating a sectioning signal from the primary and secondary retention signals; and the comparison means for collating the auxiliary signal with the sectioning signal and creating a binary output signal. The primary retention means have been adapted to maintain the primary retention signal in such a way that the value of such signal corresponds to the maximum value of the auxiliary signal. Also, the secondary retention means have been modified to maintain the secondary retention signal in such a way that the value of said signal corresponds to the minimum value of the auxiliary signal. da jiyjg - - - "A device like the one described in the opening paragraphs is already known as evidenced by European Patent Application EP 814 462. The read signal is formed by relatively high frequency components; components represent information stored in the record transmitter.Also, the reading signal has elements of relatively low frequency that act as a means to control the movement means.The amplitude of the reading signal may vary as a result of different causes ( eg fingerprints on the disk.) As a result, the auxiliary signal varies on the basis of a central value, which is also variable.In the apparatus of which one already has knowledge, the means for the combination of signals, said by the way they are formed by an adder and a multiplier, they receive the primary retention signal from a top retention detector and the Secondary retention signal from a lower retention detector. The value of the primary retention signal gradually decreases at given intervals, and the output value is higher than the auxiliary signal at the input of the upper retention detector. The combination of the three elements (the upper and lower detent detectors, and the output means) allows the device to adapt the sectioning level in such a way that changes in the central value are relatively slow; in this way, binary output signals that are reliable can be obtained. In addition, the device has a unit for the detection of defective signals, which allows it to retain the --- '- - - - fft < ? ? irttMra, -jfc A 'signal from the upper or lower detector in case there is no reliable auxiliary signal. A disadvantage of the device which is already known is that the means for generating binary signals can not follow the rapid changes of the central value of the auxiliary signal. The object of the invention is to provide a device such as the one described in the opening paragraphs that can avoid this disadvantage. Thus, the device in question is characterized in that the means for primary retention have been modified to temporarily maintain the value of the primary retention signal in such a way that said value corresponds to the minimum value of the auxiliary signal plus an additional value . Likewise, the device is characterized in that the means for secondary retention have been modified to temporarily maintain the value of the secondary retention signal in such a way that said value corresponds to the maximum value of the auxiliary signal minus a given value. In those cases in which the auxiliary signal varies around a constant central value or with slow change levels, the primary retention value will continue to be less than the auxiliary signal plus an additional value. In the same way, the value of the secondary retention signal will remain higher than the value of the auxiliary signal minus a given value. Therefore, in such circumstances, the level of sectioning will be based on the upper and lower retention value of the auxiliary signal. However, if the value of the auxiliary signal plus the additional value (increased value) decreases until the value is less than the higher value, then the output of the ^ ^^^ j ^ g ^^^^ primary retention means will be calculated based on the increased value. Similarly, if the value of the auxiliary signal minus the subtraction value (decreased value) is increased to that value is higher than the lower value, then the output of the secondary retention means will be calculated based on the value decreased . This allows the binary signal generating means to adapt quickly to variations in the properties of the auxiliary signal. It should be emphasized that the US application USP 5 412 692 discloses information about a device that has means generating binary signals that include a maximum value detector, a minimum value detector, a voltage decrease circuit (shift- down circuit) and a voltage increase circuit (shift-up circuit). The level of sectioning is determined based on the average value of the signals generated by the circuits of decrease and increase of the voltage. Generally, this average value involves an error proportional to the difference between the values generated by the aforementioned circuits. However, the influence of said error on the accuracy of the resulting binary signal increases during the intervals in which the primary auxiliary signal has a small amplitude. In the device described in this document, in such circumstances the sectioning signal is calculated from the upper and lower retention values, whereby the error in the sectioning signal is thus reduced. These and other aspects of the device are described in greater detail with reference to the accompanying drawings. Figure 1 shows the arrangement of the device according to the invention. Figures 2A and 2B show in more detail the parts of the means generating the binary signal of the device shown in Figure 1. Figures 3 and 4 show the signals that occur in the device described in Figures 1, 2A and 2B. Figures 5A and 5B show the parts of the means generating the binary signal in another arrangement of the device according to the invention. Figure 1 shows a device for controlling a register transmitter (1). The device has a transducer (2) to generate a read signal (Sr). In response to the patterns registered in the record transmitter. In the arrangement shown in the figure, the record transmitter is formed by an optical disk; however, it may contain any other type of recording medium (eg disc or magnetic tapes, cards, etc.). The transducer may move relative to the optical disc by means of the sliding plane (3) and its attached motor ( 4). In addition, the register transmitter can rotate by using the shaft motor (5). Both motors, the displacement and the axis, are controlled by a microprocessor (6). The device has means for generating an auxiliary signal (7), which are formed by a low-pass filter to derive an auxiliary signal (Sa) from the read signal (Sr). The auxiliary signal (Sa) has a relatively lower frequency than the read signal (Sr). In the current arrangement, the auxiliary signal (Sa) is the central opening signal which is passed through the low pass filter, but may be another low frequency signal (eg, a focus error signal). The primary retention means (8) receive the auxiliary signal (Sa) and generate the corresponding retention signal (H1). Similarly, the secondary retention means (9) receive the same signal and generate the secondary retention signal (H2). The primary and secondary retention signals (H1 and H2) are added using the summing device (10). Subsequently, the divider (11) divides the resulting signal by two to generate the seclection signal (St). The units of addition and division (10 and 11) constitute the means for the combination of the signal. The primary retention means (8) have been adapted to temporarily maintain the primary retention signal (H1) at a value that substantially corresponds to the maximum value of the auxiliary signal (Sa). The secondary retention means (9) have been modified to temporarily maintain the secondary retention signal (H2) at a value corresponding substantially to the minimum value of the auxiliary signal (Sa). further, the device has comparison means (12) for collating the auxiliary signal (Sa) with the sectioning signal (St), and in this way generating a binary signal (Sb). The primary retention means (8), the secondary retention means (9), the combination means of the signal (10 and 11) and the comparison means (12) as a whole form the means for the generation of the signal binary (Sb) from the auxiliary signal (Sa). The primary retention means (8) have been modified further so that they temporarily maintain the primary retention signal (H1) at a value that substantially corresponds to the minimum value of the auxiliary signal (Sa) plus an additional value. Also, the secondary retention means (9) have been further modified so that they temporarily maintain the secondary retention signal (H2) at a value that substantially corresponds to the maximum value of the auxiliary signal (Sa) minus a subtraction value. The primary retention means (8) in the first arrangement of the apparatus in question are shown in greater detail in Figure 2a. The primary retention means (8) are composed of a summing device (81), which has the function of increasing the auxiliary signal (Sa) by adding an additional value?; a minimum detector (82), whose function is to generate a signal corresponding to the minimum of the obtained signal and an intermediate signal (in other words, the primary retention signal H1). The output signal of the minimum detector (82) is coupled with the first input signal (83a) of the interruption device (83). The second input signal (83b) of the switch (83) is coupled to the microprocessor (6). Through the interruption device (83), it is possible to load the current value H10 to the delay element (84). The current value H10 is equal to the value of the auxiliary signal (Sa) - in this case it is the central opening signal that has passed through the low pass filter - during track tracking mode more the additional value? The primary retention means (8) shown in this graph also include a maximum detector (85), which has the function of generating a primary retention signal (H1) that corresponds substantially to the maximum value of the auxiliary signal ( Sa), and an intermediate signal. Subsequently, the delay device (84) receives said intermediate signal. The maximum detector (85) has an interruption device (86), which has a first input (86a) for the reception of the auxiliary signal (Sa). The second input (86b) is coupled to the delay element through the input (87a) of the subtraction element (87). An additional input (87b) of the subtraction element (87) receives a signal of disintegration? The output signal of the comparator (88) controls the interruption device (86). The comparator has a first input (88a) to receive the auxiliary signal (Sa), and a second input (88b) to receive the output signal of the delay element (84). The comparator (88) generates an output signal that indicates whether the auxiliary value (Sa) is greater than the value of the intermediate signal that was received from the delay element (84). The primary retention means operate in the following manner. By means of the current control signal (Pe), the interruption device (83) is made to enter a current mode, so that in this way it accepts the current value H10 at its second input (83b). Subsequently, said value H10 is loaded to the delay element (84). Once the delay element (84) has received the current value H10, the polarity of the current control signal (Pe) is reversed to cause the interruption device (83) to enter operational mode, as shown by the diagram; once in this mode, the device accepts the signal from the minimum detector (82). Once this is done, the output of the delay element (84) is compared with the auxiliary signal (Sa). In case the value of the auxiliary signal (Sa) is greater than or equal to the output of the delay element (84), the interruption device (86) must assume a first state in which it must choose the auxiliary signal ( Sa) of his first entry (86a). If the value of the auxiliary signal (Sa) is smaller than the output of the delay element (84), the interruption device will assume a second state, in which it will have to select the output of the subtraction element (87). The value of the minimum detector output (82) must be the value of the primary retention signal (H1) or the value of the auxiliary signal plus the additional value (Sa +?), Whichever is less. In track following mode, the central opening signal (Sa) has a constant value that corresponds substantially to the minimum value in the track jumping mode. For this reason, the secondary retention signal (H2) can be based on the auxiliary signal (Sa) without compromising its accuracy. However, the maximum value of the signal (Sa) can only be measured during the track jumping mode. This can be a disadvantage, since the level of sectioning (St) and therefore the binary signal (Sb) || jÍ ^ ^ ^ jíj ^^ may not be reliable enough when entering the track jumping mode; this can result in a wrong track count. In the diagram, the primary retention signal receives as initial value the value H10, which is equal to the value of the signal Sa measured during the track tracking mode (track following mode) plus the additional value?. The value H10 is an estimate of the maximum value of the auxiliary signal (Sa). This allows the device to generate a binary signal (Sb) that is reliable immediately after entering the track jumping mode. The secondary retention means shown in Figure 2B are analogous to the primary retention means; they only differ in the following aspects. Instead of the addition device (81), the minimum detector (82) and the subtraction element (87), the secondary retention means (9) have a subtraction element (91), a maximum detector (92) and a summing device (97) Instead of the comparator (88) shown in Figure 2, the secondary retention means (9) have a comparator (98) that determines whether the value of the auxiliary signal is less than The other elements of Figure 2B are equivalent to the elements of Figure 2A but with a reference number increased by 10. The operation of the device shown in Figures 1, 2A and 2B is illustrated referring to Figures 3 and 4 Figure 3 shows the auxiliary signal (Sa), the auxiliary signal plus the additional value (Sa +?) and the signal ^ m ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the subtraction value (Sa -?). In addition to this, in Figure 3 the primary retention signal (H1) and the secondary retention signal (H2) are indicated with dotted lines. From (sio), the value of the primary retention signal is acquired by loading the value H10 through the interruption device (83) to the delay element (84). In the time interval from a (sic) to t1, the value of the auxiliary signal (Sa) is less than the value of the output signal of the delay element (84). In this time interval, the interruption device (86) selects the signal from its second input (86b). As a result, the primary retention signal (H1) is equal to the output of the delay element (84) minus the disintegration value?. In this time interval, the value of the primary retention signal (H1) is less than the value of the increased signal (Sa +?). Therefore, the output signal from the minimum detector (82) that is delivered to the delay element (84) through the interrupt device (83) is equal to the value of the primary retention signal (H1). As a consequence, the value of the primary retention signal (H1) is reduced in the direction of the staggering in the time interval from t0 to t1. in the time interval from t1 to t2, the value of the output signal of the delay element (84) is smaller than the value of the auxiliary signal (Sa). In this case, the interruption device (86) selects the auxiliary signal (Sa) of its first input (86a), so that in this way the primary retention signal (H1) is equal to the auxiliary signal (Sa). In the interval from t1 to t2, the value of the primary retention signal (H1) is still lower than the value of the auxiliary signal plus the additional value (Sa +?). For this reason, the value of the primary retention signal (H1) is loaded to the delay element (84) through the minimum detector (82) and the interruption device (83). After t2, the primary retention means (8) temporarily maintain the value of the primary retention signal such that the value of said signal substantially corresponds to the maximum value of the auxiliary signal (Sa) detected at t2. In this case, a substantial correspondence can be defined as a difference no greater than 10% of the peak-to-peak value of the auxiliary signal. The duration of such substantial correspondence between the value H1 and said maximum value will depend on the decay factor? and the speed with which a new value of the primary retention signal is calculated. During the interval between t4 and t5, the operation of the primary retention means (8) is identical to the operation in the interval between t2 and t3. In the interval between t3 and t4, the operation is identical to the operation between t1 and t2. In the interval between t5 and t6, the value of the auxiliary signal plus the additional value (Sa +?) Is less than the value of the primary retention signal (H1). The output of the minimum detector (82) is now equal to the value of the increased signal (Sa +?), Whereby said value is loaded to the delay element (84) through the interruption device (83). Subsequently, the comparator (88) detects that the value of the output signal of the delay element (84) is greater than the value of the auxiliary signal (Sa), so that in this way the interruption device (86) selects the signal coming from the means of subtraction (87) that is located in its second input (86b) as the primary retention signal (H1). As a result of such a procedure, the primary retention signal substantially follows the increased signal (Sa +?) In the interval between t5 and t6. Subsequently, the primary retention means (8) temporarily maintain said signal (H1) in such a way that its value corresponds to the minimum value of the increased signal (Sa +?). In the interval from t7 to td, the value of the auxiliary signal (Sa) is smaller than the value of the output signal of the delay element (94). As a result of the above, the interruption device (96) selects the auxiliary signal (Sa) as a secondary retention signal (H2). Now this value is higher than the value of the auxiliary signal minus the subtraction value (Sa -?), Whereby said value H2 is loaded to the delay element (94) through the maximum detector (92). In the next interval from td to t9, the value of the auxiliary signal is higher than the output value of the delay element, whereby the interrupting device selects the output signal of the summing device as a retention signal high school. The value of the secondary retention signal is still higher than the value of the decreased signal (Sa -?), So that the delay element receives the secondary retention signal. In this time interval, the secondary retention means (9) temporarily maintain the value of the signal H2 in such a way that its value corresponds substantially to the minimum value of the auxiliary signal (Sa) that has been detected in t8.

In the interval from t9 to t10, the value of the diminished signal (Sa -?) Is higher than the value of the secondary retention signal (H2), so that the delay element (94) receives the previous one decreased signal (Sa -?) through the maximum detector (92). The value of the output signal of the delay element (94) is smaller than the value of the auxiliary signal (Sa). For this reason, the interruption device (96) selects the output signal of the summdevice as a secondary retention signal (H2). Said signal H2 now substantially follows the diminished signal (Sa -?) Until it reaches t10. After t10, the secondary retention means temporarily maintain the value of said signal H2 in such a way that its value corresponds substantially with the maximum value of the diminished signal (Sa -?). Figure 4 again shows the auxiliary signal (Sa) and the primary and secondary retention signals (H1 and H2). In addition, Figure 4 shows the sectionsignal (St) and the binary signal (Sb). From Figure 4, it is clear that in the device accordto the invention, the sectionsignal (St) is adapted to the auxiliary signal to thereby obtain a reliable binary signal (Sb) even when there are variations in the average value of the auxiliary signal. In the diagram, the additional value is equal to the subtraction value. Both values are equal to a fraction of the normal amplitude of the auxiliary signal, that is, between 0.6 and 1.0 of the amplitude. In this case, the values are equal to 0.75 of the normal amplitude. In the diagram, both the means of ^^^^^^^^^^^^^^^^ ü ^^^^^^^ ín ^^ T ^ g ^

Claims (1)

1. The value of the primary retention signal is maintained at the maximum detected value of the auxiliary signal. In the interval between t5 and t6, the value of the increased signal (Sa +?) Is smaller than the value of the primary retention signal (H1). Now the BOTT signal acquires the value of true, so that the output value of the counter (100) follows the increased signal (Sa +?). At t6, the increased signal (Sa +?) Has already reached the minimum value. In the immediate interval after t6, neither of the two TOP or BOTTOM are active, so the value of the primary retention signal (H1) is kept at the minimum value of the increased signal (Sa +?). Figure 5B shows the secondary retention means (110-113) in another arrangement. The operation of such means is analogous to that of the primary retention means shown in Figure 5A. It is important to note that the scope of protection of the invention is not limited to the arrangements described herein. The scope of protection is not limited to the number of references included in the clauses. The verb 'count' (its conjugations and synonyms in Spanish) does not exclude other parts besides those mentioned in the clauses.The words 'a', 'one' before the elements do not exclude plurals. CLAUSES: 1. A device for the control of the transmitter of records (1). Said apparatus has a transducer (2), whose function is to generate a read signal (Sr) from the patterns registered in the r ^ ij ^ M | flfi ¿? ^ ^ ^^^^^^^ L ^ ^ ^ record transmitter, as well as with movement means (3, 4, 5) to change the position of the transducer (2) with regarding the transmitter of records. Said apparatus has means (7) necessary for the generation of an auxiliary signal (Sa) from the read signal (Sr). Said auxiliary signal has a frequency relatively lower than the reading signal. The device also has means (8, 9, 10, 11, 12) necessary for the generation of a binary signal (Sb) from the auxiliary signal (Sa). This includes the primary retention means (8) for the generation of the corresponding retention signal (H1); the secondary retention means (9) for the generation of the corresponding retention signal (H2), the means for the combination of signals (10, 11), which have as a function the generation of a sectioning signal from the signs of primary and secondary retention (H1 and H2); and the comparison means (12) for collating the auxiliary signal (Sa) with the sectioning signal (St), as well as for producing a resulting binary signal (Sb). The primary retention means (8) have been adapted to maintain the primary retention signal (H1) in such a way that the value of said signal corresponds to the maximum value of the auxiliary signal (Sa). Also, the secondary retention means (9) have been modified to maintain the secondary retention signal (H2) in such a way that the value of said signal corresponds to the minimum value of the auxiliary signal (Sa). The primary retention means (d) have been modified further so that they temporarily maintain the primary retention signal (H1) at a value that substantially corresponds to the minimum value of the auxiliary signal plus an additional value (Sa +?). Likewise, the secondary retention means (9) have been modified even more so that s guts character s cas. The rest of the camera has a maximum detector (85), whose function is the generation of an intermediate signal and a signal (H1) that at least corresponds substantially to the maximum of the auxiliary signal (Sa). Also, such retention means have a minimum detector (82) for the generation of an intermediate signal and a signal corresponding to the minimum of the auxiliary signal plus the additional value (Sa +?). 3. The device described in clauses 1 or 2 has the following characteristics. The secondary retention means (9) have a minimum detector (95), whose function is the generation of an intermediate signal and a signal (H2) that corresponds to the minimum of the auxiliary signal. Also, such retention means possess a detector ^^^^ títj ^ ¡Sj & £ of maxima (92) for the generation of an intermediate signal and a signal that corresponds to the maximum of the auxiliary signal minus the subtraction value (Sa -?). 4. The device described in clause 1 has the following characteristics. The primary retention means possess the following elements: counting means (100) to generate the primary retention signal (H1); primary comparison means (101) for generating a control signal (SUPERIOR) that tells the counter if the value of the auxiliary signal (Sa) is greater than the value of the primary retention signal (H1); and secondary comparison means (102) for generating a control signal (BOTTOM) that tells the counter if the value of the primary retention signal (H1) is greater than the value of the auxiliary signal plus the additional value (Sa + ?) 5. The device described in clauses 1 or 4 has the following characteristics. The secondary retention means have the following elements: secondary counting means (110) for generating the secondary retention signal (H2); tertiary comparison means (112) for generating a third control signal (BOTTOM) that tells the counter if the value of the auxiliary signal (Sa) is less than the value of the secondary retention signal (H2); and quaternary comparison means (111) for generating a fourth control signal that tells the counter (110) whether the value of the secondary retention signal (H2) is less than the value of the auxiliary signal minus the subtraction value ( Sa ^^^^ j ^^ e ^^ íj ^^^^^^^ - ^^^^^^^^^^^^^^^^^^^^^^^^^^^? . 6. The device described in clauses 1 to 5 has the following characteristics. The primary retention means (8) have leakage means (87), which have the function of gradually reducing the value of the primary retention signal (H1). 7. The device described in clauses 1 to 5 has the following characteristics. The secondary retention means (9) have leakage means (97), which have the function of gradually reducing the value of the secondary retention signal (H2). 8. The device described in the previous clauses has the following characteristics: The primary and / or secondary retention means have programming means (83) for establishing the initial values of the retention means at a current value (H10) . "«