SE429707B - TONAL STRETCH CIRCUIT - Google Patents

Description

10 15 20 25 30 35 8204441-5 2 due to the fact that the tone generators have a certain operating voltage range.

Telephone extensions with tone generators increase the load on the ring leading to a further reduction in the available voltage ningen. Thus, the value of the current available for tonnage is generates a critical, sensitive factor. In addition, problems arise due to the fact that tonal generator circuits often show a tendency to react on selector pulses or switching transients and thereby - incorrectly ge and ton. _ _ Q ' The present invention has for its object to eliminate this disadvantage, which is achieved by the fact that the tone generator circuit exhibits them the features defined in claim 1. The tonal master circuit includes The only sensing means for distinguishing between valid and invalid ringtones by considering the duration of the ringtone above a certain, fixed voltage level. This effect is achieved by initiating comparison and then integration of the input voltage. Under it interval when the input voltage exceeds a first reference voltage level, a capacitor is charged from a first power source. Otherwise discharged the capacitor of a second power source. If the input voltage is caused by a valid ringtone, the capacitor will be charged to a voltage exceeding a second reference voltage level, at which time the tone generator is activated and the converter emits sound. About the input voltage is caused by a selector pulse or switching transient, the the capacitor not to be charged sufficiently for its voltage to exceed the second reference voltage level, so the converter prevented from sounding. Thus, conventional ringtones will be able to activate the tone generator and cause an audible output signal, during that transients and pulses up to levels of several hundred volts are incapable of doing so.

The invention is described in more detail below with reference to attached drawing. Pig. 1 is a block diagram of an electronic tone generates and shows the most important functional circuit components in the tone generator and their association with each other in accordance with the finding. Pig. 2 and 3 is a schematic schematic diagram showing the detailed circuit in an embodiment of the electronic the tone generator of the present invention. Pig. U illustrate it the interrelationship between Figs. 2 and 3. Figs. 5 shows a signal gene rator circuit according to another embodiment of the invention. 10 20 25 YES 35 HO 8a20444 ”: - 3 s Pig. 1 shows a functional block diagram of a tone generator working according to the principle of the invention. As can be seen from the figure in the tone generator power conversion means 200 connected to a pair incoming lines 101, 102, over which incoming ringtones received. The function of the conversion means 200 is to rectify it incoming ring signal and also serve as a power source for residual part of the tonal master circuit. This also includes voltage limitation circuits to limit the maximum voltage generated the rest of the circuit. In addition, the power conversion means 200 serves as a voltage source which drives the electroacoustic over line 103 the converter 300.

Sensing means H00 are connected across the output means of the conversion means 200. lines 104 and 105. These bodies N00 establish the existing of a valid ringtone. Discrimination between valid ring signals and selector pulses or switching transients are determined by the input signal voltage remaining over a reference time for a longer period of time. purge voltage level. over lines 10k, 105 are also connected oscillation generators rator means 500, which generates the signal driving the circuit means 703.

The frequency at which the generator means 500 operates is controlled by the frequency determining means 600. During a working condition, the frequency the tuning means that the generator means operate at a fundamental frequency, transmitted to the converter via the circuitry 700. During a second operating conditions cause the frequency determining means 600 to the generator means 500 emits a frequency-shifted output signal which the means 700 are transferred to the converter 300. In the output circuit input 700 includes a latch circuit which, when actuated by the sensing means 400 is switched on and off at a rate determined by the generator means 500. When the circuit means 700 are activated by both the sensing means 400 and the generating means. 500, they establish via the line 106 a current path from the the converter to the line 105. ' Fig. 2 shows a detailed principle diagram for the tone generator circuit according to Fig. 1. The incoming ring signal on lines 101, 102 is input to the power conversion means 200, namely to a diode bridge consisting of diodes 201-ZOH and also a diode 205. To the latter diode 205 is connected to an electroacoustic transducer 300 and circuit organs 700, which will be discussed in more detail below. Diode bridge one output is connected to a diode 206, which in combination with a capacitor 207 transmits power to the tonal current circuit components.

The output of the diode bridge is also connected to a resistive voltage w 20 25 30 35 40 '820444í-3 divider network consisting of resistors 208, 209, 210. A socket, point of this voltage divider leads to a Darlington transmission resistors 211, 212, which supply a voltage regulator formed by transducer the transistors 213, 21k, 215. The transistors 213 and 215 operate as a result of reverse direction breakthroughs at their base-emitter transitions as zener diodes. These transistors have several functions { with resistors 208, 209, 210 and transistors 211 and 212 they limit the maximum voltage at point 11 to a certain level.

This restriction provides a safe margin to the maximum allowed the voltage for it in the manufacture of the integrated tone generator circuit use conventional technology with embedded collector. For secondly, at point 12 they give a voltage which is used as an indication to the sensing means 400, see below. Finally provides transistor 215 is a voltage reference used to determine the current in all power sources in the tone generator circuit.

The voltage determined by transistor 215 at point 13 provides a current determined by resistors 216-220 and transistors _nas 221, 222, 223 base-emitter voltage drops. The emitter of transistors 221 current (minus the negligible base current of this transistor) constitutes tower 224 emitter current (if one disregards the transistors 22U and 225 small base currents). Transistors 22%, 225 and 226 and transistors the sensors # 01, 402, H03 in the sensing means H00 thereby form a current mirror, where the emitter current of the transistor 22H is reflected or proportioned. emitted in the emitters of the current mirror transistors in accordance with the punch value in the respective emitter line. Thus, the current is in the emitter leads of the transistors 226, 402 and H03 are twice as large as the emitter current of the transistor 224 because the respective emitters resistors 227, HON and H05 amount to half of resistor 228 value, while the emitter current of transistor # 01 due to "resistor 406 is twice as large as resistor 228 is half of the current in the transistor 22%. It should be noted that the number of indifferent collectors' for each transistor are indicated by the number of collectors leads. Transistor 225 is used as an auxiliary transistor for current the base drive of the mirror. Due to the fact that the transistor 226 has split collector with equal areas, each collector will - designated "a" and "b" - to carry half of the total emitter current. Further the emitter current of the transistor H01 is divided into five different large parts by means of the five collectors, with three-fifths of the current being led to ground point and one - fifth to each of points 14 and 15. 10 15 20 25 30 35 NO 82044-43-3 5 In accordance with the instructions given by T.M. Frederiksen, W.M.

Howard and D.M. Monticelli in the essay “A Single-Chip, All Bipolar, Camera Control IC "- presented at the 1977 IEEE International Solid State Circuits Conference, February 18, 1977, and reproduced in "ISSCC Digest of Technical Papers ", pp. 21H-215 - divided into transistor 407 emitter current in five equal parts, four of which are shunted to ground and the remaining part is fed to the transistor H08 collector. This transistor forms together with the transistors N09 and 410 an additional current mirror with the transistor H11 operating as auxiliary transistors. Transistor H12 is used to make transistors H1 and 413 base currents are equal in magnitude by via the transistor H10 collector current compensates the base current of the transistor N13. This current is carries a significant addition to the capacitor's H1U discharge current if the gain of the transistors were low. Transis- tores H09, H10 and 412 emitter currents have established values such as depends on the relative size of the emitter transitions (indicated by number of emitter conductors) and the values of the emitter resistors.

The collector b of the transistor 401 is connected to the emitters of a differential coupled transistor pairs H15, N16, which form a comparator with one pair of transistors always on. When the transistor N16 is conductive, the current is conducted from the transistor's H01 collector b to ground.

On the other hand, when transistor H15 is conducting, four-fifths of the current is but from the transistor RO1 collector b to ground and one-fifth more point 16 for charging the capacitor ß1H.

The transistor's 22% collector current is essentially the same as the emitter current of the transistor 223 (disregarding the base currents).

Transistor 223 forms a current mirror with transistor N17 in Fig. 2 and transistors 601, 502 and 503 in Fig. 3. Transistor 222 is used as auxiliary transistors for this current mirror.

The function of the sensing organ depends on the voltage level at the point 12 and on the voltage across capacitor 414. As soon as input voltage of sufficient size is supplied, transistor 215 begins to perform its control function and the power sources are activated, the Transistor 215 read in the control state of the current in the collector a of the transistor 226 a.

Constant voltages are established along the resistance chain 216-219 and these voltages are taken out as voltage references. Voltage the reference at point 17 is used in the generator means 500 as a disk later, while the voltage reference at the one with the transistor point 18 connected to tower N18 establishes the minimum voltage densifier H14 is allowed to charge to. Point 19 provides one = 10 15 20 25 30 35 H0 s2 @ 444 @ -3 6 reference voltage for the base of the transistor H19. Transistor 419, driven, via the resistor H20 of the current in the collector b of the transistor 226, supplied maintains a voltage at the base of transistor N15 when transistor 433 is strangled. Transistor H16 has its base connected to point 12, whose voltage is proportional to the full-way rectified voltage.

As previously indicated, the differential cup control the transistor pair, 415, 416 the charge of the capacitor 414. When the voltage The voltage at point 12 is lower than the reference voltage at the transistor H15 base, transistor 416 is conductive and transistor 415 is throttled, when the current through the collector b of the transistor H01 flows to earth. Un- this time, the capacitor 414 is discharged by the collector of the transistor N10. Current. When the voltage at point 12 is higher than the voltage at However, the base of the resistor H15 is the transistor N15 conducting and tower U16 throttle, the current in the collector of transistor 415 a min- damage with the current of the transistor H10 is used to charge the capacitor RTR. The voltage across capacitor 41k will rise according to one triangular waveform determined by the time during which the voltage in point 12 is greater than the voltage at the base of transistor N15. Through use of small charging and discharging currents can condense tower Hlk be relatively small and inexpensive.

Transistors H09, 413, R17 and 421-42k form an amplifier with the gain one and acts as a buffer between the high-impedance diva point 16 and the lower impedance having the base of the transistor torn_U25. Transistors 425 and H26 form a differential pair.

The base of transistor 426 is supplied with a reference voltage determined by sistor H03 constant collector current, a voltage level change transistor N27, resistors H28, H29, N30 and H31 and the current in transistor 425.

When the voltage across capacitor H14 is lower than the voltage at the base of transistor H26, transistor 425 is conductive and transistor H26 throttled, with the collector current of transistor # 02 via the transistor H25 and resistor # 30 float to ground. This extra current through the position 430 raises the voltage at the base of transistor H26 and provides more circuit hysteresis in the following way. When the capacitor H14 is charged enough to raise the voltage at the base of transistor N25 to approximately the same voltage as at the base of transistor H26, more transistors to turn on so that the transistor H25 is throttled and transistor # 26 becomes conductive. At this point, three things happen at the same time. First, three quarters of transistor 426 flows emitter current to the circuit means 700, which will be discussed later, so that 10 15 20 25 30 35 HO 82044-4É-5 1 these are activated and allow ringing to start, as the the rator means 500 at this time generates a signal. For it second, a quarter of the emitter current of transistor 426 flows to the collector and base of transistor N32, which together with transistor 433 forms a current mirror. The relationship between the issuer resistors HSR and 435 for transistors N32 and 433 is such, that the collector of the transistor H33 emits a current which is subtracted from the current in the collector b of the transistor 226, leaves a low current through the resistor H20. This current reduction serves to reduce the reference voltage at the base of transistor 415 to a level which is sets the tone generator to remain on once it is turned on started to sound. Such a reduction is necessary, since the converter the load - after the tuner has started working - causes that the incoming ring voltage falls below its positive half- periods. Finally, the collection floating through the resistor N30 ceases. the current through the transistor H25, the reference voltage at the base of the transistor ü26 is lowered to a level which ensures that the the generator remains on. After a valid ringtone has been identified locking will thus be ensured as a result of the reference level the shift. Selector pulses and other transient signals are not detected by these bodies because their levels and durations exceed the reference the voltage at the base of the transistor R15 is less than resp. shorter than that incoming ring voltage. Thus, the capacitor N1U is not charged sufficient for the reference voltage at point 30 to be exceeded, why ringing is absent at such signals.

Fig. 3 schematically shows the generator means 500 of the tone generator circuit, frequency determining means 600 and circuit means 700. Generator means 500 functions in a similar way to the sensing means H00 in this respect that charging and discharging a capacitor by means of complementary connected constant current sources are used to set the frequency and heart rate ratio. In this case, a capacitor 505 responds to the charging and discharge current sources, which are constituted by the transistors SOM resp.

S03. Depending on which of the differential pair transistors 506 or S07 which is conductive, capacitor 505 will either be charged or discharged. As previously indicated, transistors 501, 502 and 503 part of current mirrors formed by transistor 223 shown in FIG. 2.

The collector currents of the transistors 502 ohh 503 are equal after all power sources are enabled. If the transistor S10 is throttled, the the reference voltage at point 17 (Fig. 2) minus the base of the transistor SO emitter voltage Vbe plus voltage drop across resistor 514 att 210 20 25 30 HO 8204441-5 5 8 appear at the base of transistor 506. To begin with, the capacitor 505 is discharged, so that the base of the transistor 507 is at a lower power than the base of transistor 506, which causes transistor 507 to be throttled and transistor 506 conductive. As a result, the transistor floats 502 collector current through the transistor 506 and becomes substantially trans sistor 509 emitter current. Transistor 509 here forms a current mirror with transistors 602, 510, 504 and 511. Transistors 512 and 513 form a Darlington auxiliary transistor for delivering base l current to the current mirror.

The current through the transistor 510 flows through the resistor 514 and transistor 501 to ground. The voltage drop across the resistor the stand 514 is added to the emitter voltage of the transistor 503 and increases the voltage level at the base of transistor 506. At the same time, the trans- collector current of the resistor 504, reduced by the collector current of the transistor 503 current, capacitor 505, and transistor-511 collector current flows through the resistor 515 and opens the transistor 516. When the transistor tower 516 is conductive, the output transistor 701 is prevented from opening independent of the presence of collector current of the transistor H26. Condensed The sensor 505 continues to be charged by the transistors 503, which shot collector current until the charge reaches a voltage level equal with the level at the base of transistor 506. Shortly thereafter, the transistor becomes 506 base-emitter junction biased in the reverse direction due to it reduced the current through transistor 510, and transistor 507 the base-emitter junction is biased in the forward direction, thus transistor 507 turns on and transistor 506 turns off. The switching of these two transistors are promoted by the transistor 517 with split collector. At this time, the collector current of transistor 502 flows through transistor 507, and the current built up around transistor 509 the mirror turns off. The introduction of the resistor 518 improves this power mirror switch-off properties.

When transistors 507 and 506 change state, the transistor the base voltage of the resistor 506 that with the voltage drop across the resistor 51U lowered to the original reference voltage level. The capacitor 505 then begins to be discharged by the constant carbon of the transistor 505. senior lecturer. Furthermore, the base drive of the transistor 516, which therefore strangled. If a valid ringtone has been detected in accordance with as discussed above, transistor N26 will output current to the circuit means 700 so that - when the transistor 516 is throttled - f the current in transistor 426 serves to drive the circuit means 700 transistor 701 to conduction state. In this way is thus achieved 10 15 20 25 30 8204441-3 an inversion of the oscillator output voltage. Capacitor 505 then continues to be discharged via transistor 503 Üíll ÖGSS that its voltage has dropped to the voltage level at the transistor 506 bas. At this time, transistor 507 is throttled below it that the transistor 506 turns on again and supplies them around the transistor tower 509 mirrored the power sources. The base of the transistor 506 returns to its previous voltage level, capacitor 505 begins to is charged and the oscillation is repeated.

The frequency determining means 600 allows the possibility of an output signal of frequency modulated type by oscillating the generator means 500 ring frequency is shifted during the negative of the incoming ring voltage. tiva half periods. The frequency determining means include transistors 601-BOH and resistors 605-610. The possibility of frequency shifts is achieved by passing the base of the transistor 604 via the resistor 610 and a switch such as switch 611, is connected to line 102 in Fig. 2.

During the negative half-periods of the input signal, the transistor BOR to be biased in the forward direction so that base current is shunted away the transistor 601, which is hereby throttled, as well as the transistor G03. This mode of operation allows the transistor 602 to become part of the circuit system 509 formed the current mirror so that current can be shunned from transistor 510 via resistor 608 and transistor 602 to ground.

The result is that lower voltage is generated at transistor 506 base, which in turn reduces the voltage at which to the capacitor '505 must be charged to bring the transistors 506 and 507 to switch. This in turn reduces the capacitor 505 charging and discharging times, thus increasing the frequency of the oscillator kvens. During the remaining negative input signal periods, the transistor comes on 602 to cause a decrease in the collector current of the transistor 510 and thus giving rise to the increased oscillation frequency. The value of the the position 608 is selected so that the increased frequency has the harmonic the ratio 5 / H to the frequency of origin and thus gives rise to a pleasant sound. It should be noted that the pulses of the two frequencies ratios remain the same because the charging and discharging capacitors of the capacitor 505 10 _ 15 20 25 30 35 HO 10 current flows are unchanged. If the frequency shift option is not used, transistor 601 remains turned on and thus holds transistor 603 bottomed. As a result, the transistor_ remains 502, whereby no current is removed from the transistor 510 and the oscillator retains its original frequency. I. The output means 700 for the tone generator are formed by transistors 701, 702 and a resistor 703 coupled in thyristor equivalent combination nation. When a valid ring signal is identified by the sensing means H00 will, as previously discussed, have a continuous current fed from the collector of the transistor 426 to the circuit means 700. Eph. since the generator means 500 is in operation at this time, transistor 516 will turn on and off in accordance with frequency and heart rate ratio of these organs. When the transistor S16 is turned on switched, the control electrode current from the transistor H26 will pass _, its collector, so the thyristor equivalent will be throttled. il Conversely, when the transistor 516 is turned off, the thyristor equivalent will be conductive due to current supplied by the transistor N26.

The circuit means 700 as a whole also include converter connections. which is supplied with a driving power from the rectifier diode 205. Some The rectified input signal voltage is applied by means of the capacitor 705, why the resulting voltage supplied to the converter is amplitude modulated with a degree of modulation of about 40%; the amplitude the modulated input voltage thus provides the envelope to the pulse which drives. ver converter. Resistors 706-709 provide volume control for the tone generator.

The diode 710 passes through the back emf generated by the decay the voltage across the inductance of the converter 300.

The generator means 500 provided with frequency shift input are is shown in Fig. 3 as a special embodiment but can be given one more -general form, see fig. S. The generator means 500 include three power sources- S20, 521 and; 5É2, a comparator 523, a capacitor C and a resistor R. The power source 520 emits a current of magnitude I and is tinuerly at work. The power source 521 emits the current K1I and is beaten when the output signal of the comparator 523 is logic one. Power source 522 is also turned on when the output signal of the comparator 523 is logic one but emits a current of magnitude KZI or K3I depending on the the similarity of a frequency shift input signal. This relationship is evident from a truth table also shown in Fig. 5.

The comparator 523 is provided with two incoming lines A and B and an output line D. A voltage VREF is via a resistor R. connected to the input line A of the comparator A. The power source 522 is 82044--21-5 11 connected between line A and a common reference potential such as soil. Capacitor C and current sources 520 and 521 are connected between the input line B the common reference potential. Out- the thread line D, which is located at logic one of the input lines line A is at a higher level than the input line B and at logic zero if the input line A is at a lower level than the input line B, : connects the output of the comparator 523 to the power sources 521 and S22.

The frequency shift input signal is also applied to the power source 522.

Capacitor C is charged by current I from current source 520 and is charged by the current K1I from the power source 521. Since K1I is proportional to I, the net charging current can be written as (X1-1) I, The three voltage levels that can occur across the resistor R are 0.

RKZI or RK3I and depends on whether the frequency shift signal is present.

The voltage thresholds between which capacitor C must oscillate are thus either 0 and RKZI or 0 and RK3I.

For the time interval during which capacitor C is charged at logic one as output signal from capacitor 523 applies to: Å VRC 1 <2RIc xz tupbl = = _ = RC (1) Iuppl (K1-1) I (X1-1) Furthermore, applies AVRC KZRIC - (2) turl: Intl = -_l__ = K2Rc ' The period thus amounts to . K _ 2 _ tuppi * 'Curl': <1 -1 * Kz] Rc ' = 1 + 1 xxc-Káxz Rc (a) x1-1 2 '1 <-1 1 The frequency thus applies r_ 1 freq - (ll) and in the frequency shift case 1 K -1 freq = (5) K1K3RC For the heart rate ratio applies * <2 RC K1-1 _ 1 - 2: * ~ _ (6) per K K 12 Rc K1-1 š 10 15 20 25 30 s2o444z-ät 12 From the above it appears first of all that the frequency and pulse the ratio is determined by the values of the resistor R and the capacitor C and on the relationship between I and K1I and, secondly, to change of frequency by changing R, C or K2 does not affect pulse rate.

If discharge of capacitor C is taken as a starting point, the oscillator operates as follows., The voltage across the capacitor tower C and on the input line B are discharged from the power source 520 so that it becomes less than the voltage VREè on the input line A. This to change the output of comparator 523 to logic one. This this starts the current source 521 with the current K1I. An upload (K1-1) I then charges the capacitor D. The logic one from the comparator S23 also starts the power source.522 with the current KZI or Kal whereby the voltage on the input line A is increased to one voltage corresponding to RK2I resp. RK3I plus YREFr When capacitor C charged to the point where the comparator's input line B becomes more positive than the input line A, the output signal of the comparator 523 exceeds to zero. The power source 522 is then switched off, and the voltage on the input the supply line A becomes VREF again. Furthermore, the power source 521 is also closed off, and the power source S20 starts discharging the capacitor C from a voltage equal to RKZI + VREF or RK3I + VREF down to one voltage below VREF at which point the comparator output signal again changes to logic one state, after which the oscillation resumes repas. It is thus obvious_ptt the voltage swing across the condenser tower is determined by the current KZI or from the current source S22 or K3I and that the charging and discharging speeds of capacitor C are determined mes of the power sources 521 resp. 520. The period of the oscillation thus constitutes is a function of resistance: -oobh capacitor values plus current- the ratio of the sources (all K-terms constant). Since the current the sources are related to each other, in addition, the current from them vary over a large area without affecting the frequency of work provided that said conditions are maintained. Supply voltage variations will thereby have minimal effect on the oscillator working frequency. -___

Claims (3)

8204-44 n-h -s 13 Patent claims A tone amplifier circuit comprising input terminals for receiving ring signals, an electroacoustic converter (300) for generating an audible output signal, an oscillation generator means (500) for activating the electroacoustic converter and a power conversion means (200) which responds. on the ring signal over the input terminals and are arranged to supply energy to the tone generator circuit, and on the one hand sensing means (400) for distinguishing between valid and invalid ring signals printed on the input terminals, characterized in that the sensing means (400) comprise a plurality of generators (400). 401, 402, 403, 408, 409, 410, 412, 417), which are complementary arranged over output lines of the power conversion means (200) arranged for supplying energy to the sensing means (400), when a voltage is applied to the power conversion means, which current generators activate a first or a second transistor (415 and 416, respectively) in differential connection in and for charging and discharging, respectively, a capacitor (414) in response to the voltage emitted by the power conversion means (200) being above or below a first predetermined level, and which current generators supply energy to a third and a fourth transistor (425 and 15, respectively). 426), which are differential coupled and whose conduction state is inverted upon charging of the capacitor (414) over a second, predetermined voltage level, the fourth transistor (426) being connected to circuit means (700) and providing an activation signal for selectively connecting the generator means ) with the converter (300). The tonal circuit according to claim 1, characterized in that the sensing means (400) comprises locking means, which are activated when the capacitor (414) is charged above the second predetermined voltage level and which maintains the activation signal for the circuit means (700) during that time period. as a ring signal appears at the input terminals. _ 3. A tone circuit according to claim 2, characterized in that the locking means comprise a fifth and a sixth transistor (413 and 421, respectively) arranged in differential connection, the fifth transistor having its base connected to one of the multiple collector portions of the first transistor (415). ), while the sixth transistor has its base connected to the third transistor (425), which is differentially connected to the fourth transistor (426); that the third transistor is throttled and the fourth transistor is opened when the capacitor is charged above the second predetermined voltage level; that the emitters of the third and fourth transistors are jointly connected to a positive reference potential via a constant current generator (402); and the base of the fourth transistor is connected to the positive reference potential via a second constant current generator and to the negative reference potential via a series * coupling consisting of a voltage level shift circuit (427, 428, 429), a first resistor (431) and a second resistor ( 430), while the collector of the third transistor is connected to the negative reference potential via the second resistor; that the collector of the fourth transistor is divided into multiple portions, of which a first collector portion is connected to the circuit means for supplying an activation signal thereto, and of which a second collector portion is connected to a seventh transistor (432) interconnected base and collector in and for driving thereof; and that the seventh transistor forms a current mirror with an eighth transistor (433); which has its collector connected to the base of the first transistor.