DE2024744C - Method and arrangement for dynamic testing of echo suppressors - Google Patents

Description

The invention relates to an arrangement and a method for the dynamic testing of echo suppressors with a device that is an echo suppressor a test signal supplies, and having means that the response of the echo suppressor to the test signal notices.

Many telephone and similar communications are over long distance links Length. Due to irregularities in the telephone equipment used to make these connections can be reflected signals, i. H. Echo signals arise. These can then become a Become a problem and impair the transmission quality if the transmission system has a round-trip delay of more than a few milliseconds. Delays occur in typical systems from a few milliseconds to several hundred milliseconds.

In order to eliminate or reduce the effects of such echo disturbances, generally Echo cancellers used. Since most long-distance connections run through circuits with echo cancellers, the transmission quality can through Changes in the operating characteristics of the individual echo cancellers are affected. The maintenance a modern telephone system therefore requires to ensure trouble-free operation high quality periodic checking of the echo suppressors.

Generally speaking, incorrect operation of echo cancellers affects the quality of the voice transmission. For example, an echo signal to a subscriber may dei because of a delay Echo blocking operation are transmitted back, making the speech signal received by him incomprehensible will. In addition, speech mutilation can occur during a countervailing interval occur, d. H. during an interval when both parties are speaking at the same time because an echo canceller not immediately a transmission path also for the second participant of the connection through switches. When transmitting data over telephone lines, errors can occur because echo suppressors are not suspended in the transmission lines.

So far, the mode of operation of F.chosperrei evaluated according to two procedures. In one method, the echo lock to be tested is electr. decommissioned. Such a test is cumbersome, lengthy and unreliable. You give no information about the behavior in the real

normal operation. It is also assumed that an echo canceller is properly back in after the test the transmission link is switched on. However, this is by no means the rule. Having established However, it has been proven that an echo suppressor works properly under static test conditions is by no means sure that it will also work usefully in the intended transmission path.

In the second procedure, an examination is carried out by so-called experts. It tries to the echo barriers through a mutual conversation over the transmission link to be tested and evaluate an acoustic observation of the received signals. One such test method is expensive, as it is carried out by experienced specialists at both ends of the telephone line to be tested depends. In addition, the results obtained are only qualitative and always with one Uncertainty due to an external influence on the people who have such a high degree carry out subjective tests. In practice, these tests have therefore also proven to be proved little informative.

It is also a test of echo suppressors with regard to a certain property, namely the so-called overhang time, known with the help of an alternating current test signal. The overhang time, that is, the period of time for which the echo lock is still in a certain period after the test signal has been switched off State remains is determined on the basis of the charge of a capacitor that of an external Voltage source is charged via a relay contact of the echo lock. Must for the exam in this case the echo locks are also taken out of operation, and only one property can be used relatively simple echo suppressors are checked.

The object of the invention is to provide an arrangement and a method for objective testing to create echo suppressors with respect to a large number of parameters without adding the Echo locks need to be taken out of service.

To achieve the object, the invention is based on an arrangement of the type mentioned at the beginning and is characterized in that the means for supplying the test signal is a signal generator circuit for generating a large number of test signals different "frequencies that the output of the signal generator circuit via a A plurality of switching devices leads that can be actuated in predetermined combinations to supply combinations of test signals of different frequencies to an output circuit, that the combinations are chosen so that at least one frequency, a monitoring frequency and one or more other frequencies are Sieuerfrequenzen that a connection device is also provided which is used to connect the Output circuitry to the transmission line containing the echo suppressor to be tested, optional can be actuated that a control device is provided which selects a desired switch combination, so that a certain test signal combination with a control signal of suitable amplitude and Frequency for checking a certain switching function of the echo lock (ζ. B. activated or not actuated, sensitivity, differential sensitivity under burglary conditions in the actuated or non-actuated state, burglary overhang time, etc.) is applied to the transmission line simultaneously with a supervisory signal, and that the Device for determining the response of the echo suppressor to the transmission line or has another transmission line connected to this receiver, which can be connected to the signals with the monitoring frequency from the output

ίο the echo canceller picks up and detects, and one on the output of the receiver connected reading device, which depends on the output

signals from the receiver indicates whether the response

'the echo suppressor for the specific, tested function is within predetermined limits.

The inventive method for checking echo barriers in a communication circuit with a first and a second transmission path is characterized by the method

ao rens steps:

a) connecting the first and second transmission paths at the far end of the transmission circuit;

as b) Generating AC test signals that contain two or more signals of different frequencies, of which at least one represent a supervisory signal and the other or the other control signals;

c) applying a selected test signal to the other end of one of the transmission paths, wherein the test signal is chosen so that the echo trap control signals to test a certain switching function of the echo lock (ζ. B. activated or not activated, sensitivity, Differential sensitivity under intrusion conditions in actuated or non-actuated Condition, burglary overhang time, etc.) have suitable frequency and amplitude;

♦ ° d) Receiving and detecting signals with the monitoring frequency coming from the output of the echo canceller and at the other end of the other transmission path appear for the purpose of forming an output signal;

e) Evaluation of the output signal for generation a read signal that indicates whether the response of the echo lock for the specific, tested function is within predetermined limits.

Further developments of the invention are the subject of the subclaims.

In one embodiment, a circuit for dynamic testing of echo prawns in a Telephone trunk system established, inde.n over a first telephone line, i.e. a test line containing echo suppressors to be tested a loop-around unit with a second telephone line, namely an auxiliary line, connected. The test lead can contain echo suppressors at both the near and far end. The same applies to the auxiliary line. However, echo barriers in the auxiliary line are deactivated, so that the operating characteristics of the ed ^ oper-

can be correctly determined in the test lead. A plurality of selected test signals are generated in a transmitter and in a predetermined form via the test lead br * ·, the auxiliary lead to the

7 8

Echo suppression given at the near or far end, depending on Hch. That is, echo cancellers located in the

according to which echo suppressor to check. Transmission path both in the nearby office 100 and

The test signals are located at predetermined frequencies - even in the remote office 101 - can be complete

zen and are evaluated accordingly from the office 100 for predetermined intervals. The distant office the functional property (s) to be tested s 101 contains all equipment that requires a test of the

generated. These signals are intended to enable the echoes to be tested telephone lines which are used for the

»Suspend or block, lead to a special, Amt 100.

address in a predetermined manner. In a receiver, accordingly, the nearby office 100 includes a main unit it is automatically determined whether the tested test unit 110 and a plurality of test fields Echo suppressor responds correctly and therefore correctly io 120-1 to 120-n. The main test unit 110 comprises works, in that the received a transmitter 111, a receiver 112 and a Test signals corresponding to predetermined ones control unit 113. The transmitter 111 generates a multiple Test functions assigned to test signals are a number of test signals that are evaluated in each case will. leading exam or exams are adapted. A-

Accordingly, the echo suppressors in telephony units of the transmitter 111 are shown in FIG. 2 shown and

lines that have a first main office with a large number will be discussed later. The recipient 112

connect further main offices, completely processed by test signals, which are via the test system and

Tests are assessed, which in the first office either on the echo suppressor to be tested or

initiated and carried out, whereby only a -block has been given. For special test

Minimum equipment in the other offices is the receiver 112 directly to the transmitter

is required. 111 connected via a line 115. details

The invention is illustrated below using one of the receivers in FIG. 3 shown and should

Embodiment and in connection with which will be explained later. The control unit 113 controls

Drawings described in more detail. As its name suggests, it shows the functions of transmitter 111

1 shows an arrangement for checking echoes and the receiver 112 for the respective implementation blocks in a telephone connection after the first exams. The control unit 113 is so darfindung, made that they send signals to the transmitter 111 and to the

Fi g. FIG. 2 provides a simplified block diagram with one receiver 112 over line 114, but in FIG

Zeiheiten of the. Transmitter according to Fig. 1, in practice, the control functions can be

F i g. 3 is a block diagram showing details of the turn of a variety of relays or others

Receiver according to F i g. 1, switching devices are carried out in the transmitter

F i g. Figure 4 is a block diagram showing details of the and receivers are included.

Feedback unit according to Fig. 1, the transmitter 111, the receiver 112 and the control

FIG. 5 shows details of the control and timing unit 113 of the main test unit 110

Control unit according to FIG. 2, 35 test fields 120-1 to 120-n via lines 125, 126

Fig. 6 shows the circuit diagram of the oscillator and the and 127 connected. Each of the test fields 120-1 to

monostable multivibrator according to FIG. 5, 120-n can be of a known type and is ani

F i g. 7 details of the shutdown release unit associated with trunk group that the near

according to FIG. 2, Office 100 connects to a remote office. Such a «

F i g. 8 details of the detector according to FIG. 3, 40 system leads to maximum profitability, since nui

F i'g. 9 the circuit diagram of the read input setting one main test unit per telephone exchange required

unit of Fig. 3 is. The number of test fields per office was determined

10A to rOE show a sequence of curve shapes through the number of connecting line groups in

to explain the suppression test of office.

Echo locks, 45 To explain the invention is in this case

11 A to 11 D curves to explain the play around the nearby office 100 via the test field 120-1

Burglary test of echo barriers, via the "test" connection line 130 and di

12 A and 12 B curve shapes to explain »auxiliary connecting line 140 with the removed!

the switch-off test of echo barriers, Office 101 connected. The test connection line 13 (

Fig. 13 is a waveform illustrating Fig. 50 and the auxiliary connection line 140 is distant

Protection testing of echo barriers. Office 101 to produce a test circuit practice

In Fig. 1, a return unit 150 is connected on the basis of a simplified block. This is shown below

A circuit diagram shows a test system according to the invention using switching equipment 122-1

placed. Since the invention extends to the test of the test field 120-1 in a known manner

Echo suppressors are concerned in transmission links that are assigned a 55. The connection of the lines 13 <

first telephone exchange with a large number of second and 140 is thus in a known manner by * Wah

or to connect remote offices, are used to explain and transmit a special check code

tion reached two offices 100 and 101 in the drawing, the respective lines. The usage

shown. For simplicity, the connections of the auxiliary connection line 140 are in the test circuit;

between the functional blocks of the system 60 shown according to the invention simplifies both the test ver

shown as a single conductor. In practice, these can drive as well as the test system very much. Line 141

Connections, however, a multitude of cores represents an additional path that the outgoing

keep. In the offices 100 and 101 existing supply and receipt of test signals to and from de

Averaging equipment and other auxiliary test equip- ment, each tested echo blocker simplifies :. It is nu

armor is not shown. 65 a minimum of equipment in the ferrari office 10

The nearby office 100 contains all the equipment required, namely the return unit 150, derci

to initiate and carry out the examination of details in F i g. 4 are shown.

Echo blocking required in a transmission line - The test line 130 can echo blocking! *. 131 and 13

included at the near or far end. In the general network 225, a line selector 230

my four-wire lines are fed to the connection, where they can either be connected to the connection

used by telephone exchanges. Accordingly contains 231 or 232 are supplied. The line voter

The test lead 130 to an outgoing two-wire path 230 may also be of any known type

133, which is usually referred to as the transmission path, must be 5. Typically, a large number of

and an incoming two-wire path 134 using controlled relays in a known manner to control the

is referred to as a homely reception path. Making the right choice of connection. The signals are

The transmission path via the line 130 can then also be via a shutdown release network 250,

contain an underwater cable or one of its details in FIG. 7 are shown and that

Lead synchronous satellites. The auxiliary line 140 ent- io is to be discussed later, for the test transmission output

similarly holds echo locks 141, 142 and output amplifier 240 or to the auxiliary sendc output

Transmission and reception paths 143 and 144, respectively. Amplifier 245. The amplifiers 240 and 245 can

The test fields 120-1 to 120-n are again designed in a known manner. the

121-1 to 121-n assigned, which are designed in such a way that auxiliary output amplifier 245 is equipped with an amplifier

that with their help, the Kauptprüfeinheit 110 activated, 15 provided kungs setting 255 that during the

can be. In general, such calibration of the test system is used. Signals on

Control panel a multitude of pushbuttons that lead to the output of the amplifier 240 and to the output of the

Selection of certain tests for selected echo amplifiers 245 are made to transmission path 125

can be used in the line to be tested. fed.

The control fields 121 can also be designed in such a way, ao FIG. 5 shows the details in simplified form

that they have an automatic test of the telephone control and timing unit 220. A

enable lines. For example, they can be used in oscillator 501 which is a monostable multivibrator

Dependent on a magnetic tape or a 502 assigned to use timing signals with

other, in advance automatically created program of the correct duration at the outputs 515 and 516 of the

go through a series of tests. as a monostable multivibrator 502. A-

In Fig. 2, the details of the oscillator 501 and the monostable details of the transmitter 111 are shown in the form of a block diagram. Oscillators multivibrators 502 are shown in FIG. 6 shown. The outputs 515 and 516 of the morio ^ stable multiviaus at 201, 202 and 203, which can be formed in any known manner, generate signals with signals generated at brators 502 are complementary to 1000, 2100 and 2750 Hz. Preferably 30 to each other, ie, the signal at output 515 is normally these signal frequencies are used, since it is known to be “high”, ie represents a logical “1”. Typical echo barriers at these frequencies and the signal at output 516 normally respond in a predetermined manner. In connection “low” represents a logical “0”. Output signal with oscillators 201, 202 and 203 are signals at output 515 are an astable switching element 214 and 215 as well as gates 21t, 212 and 35 multivibrator 503 for generating timing -213 used to generate certain test signals at the output 520, as desired, to generate the predetermined signals. The switching elements 214 and 215 correspond to th waveforms. The astable multi are operated by the control unit 113 (FIG. 1) via the vibrator 503 only during those integers 114/4 or 114B. To explain valle, for which the signal at the output 515 of the mono, the circuit 114 contains a large number of wires, 40 stable multivibrator 502 is deep, that is, a logical one that feeds signals to the respective networks. Represented in "0". Since the signal at the output 515 can sometimes be high, the switching elements 214 and 215 may be high, but the astable multi-function device may consist of relay contacts, for example. brator 503 only when the monostable multi-die gates 211, 212 and 213, which can have any known vibrator 502 running in its unstable operating state, are located on a past 45. In other words, the astable multivibrator is correctly controlled by signals, the 503 generates a signal at its output 520 only control and timing unit 220 via line when the monostable multivibrator 502 is tuned 221, 222 and 223, respectively The shape and unstable interval runs accordingly, one duration of the signals generated in the control and timing a variety of timing signals available 220 changes with the 50 each of the lines 221, 222 and 223 and consequently the test or tests performed The unit gates 211, 212 and 213 (Fig. 2) fed to 220 is controlled by signals that can be sent from the control unit. At the outputs 515, 516 and 520 of the unit 113 (Fig. 1) via the line Thus, signals supplied to 114C may be provided as required .. Details of the control and timing by an individual or combined Be control unit 220 are shown in FIG gt. 55 actuation of relays A to E on lines 221, 22

The oscillator signals will be fed to the tuning network 223 and 223. The connecting path

225, where their amplitudes correspond to those for the signals at the outputs 515, 516 and 52

Needs to be adjusted. About the switching are through the contacts in this way

Elements 214 and 215 running signals are determined for actuated relays. For example, I will certain test functions are used, which are later converted into 60 signals at output 516 of the monostable multiv

bond with the test procedure. brators 502 of line 221 via the normally closed contact

The amplitude adjustment network 225 can, for example, relay C (normally closed contact C-2) and the normally closed contact

wise be a voltage divider network that is fed to contact 1 of relay D (normally closed contact DI)

known way using relays or without any of the relays energized. If d Similar components are influenced in such a way that 65 identical signals, i.e. the signals at output 51 Signals with certain amplitudes accordingly. to be put on line 222, d

result from the test functions to be carried out. The relay D is actuated, and the signals then flow from

Signals at the outputs of the amplitude adjustment output 516 via normally open contact 2 of the relay

u f

12th

(D-2), the normally closed contact 1 of the relay A (AI) as well as remains. - The transistor 605 remains conductive until the end of the normally closed contact 1 of the relay C (CI) and the rest unstable interval. In this way, contact 2 of relay B (B-2). The oscillator-multivibrator combinations at the other outputs are precisely controlled in accordance with the oscillator 501 and consequently the period of the oscillator mode,
Depending on the requirements, signals produced the line. 7 the details of the shutdowns 221, 222 and 223 are supplied. Release unit 250 (Fig. 2) shown. The unit

F i g. FIG. 6 shows details of a combination of 250 ensures that the tested EclM locks, an oscillator and a monostable multivibrator, which are in control and timing, before any further testing by unit 220 of FIG. 5 can be used. The io is led. In other words, the shutdown enable oscillator 501 and the monostable multivibrator unit 250 sets the .502 under test to form an astable multivibrator with varab echo locks in a position to any previous Belem duty cycle. To end such an astable multi-drive state. This is achieved in the exemplary embodiment which enables independent influencing, in that the pulse width and the pulse period and enables the lines 231 and 232 briefly with the aid of a light also have a very small pulse duty factor. When the normally closed contacts DR-I or DR-2 are opened, the oscillator 501 represents a unijunction, which ensures that, for a predetermined transistor oscillator that has a normal uni- tes interval, no test signals to the junctiontransistoroOl, a timing condenser located echo barriers can be supplied. The Konsator 602, a frequency setting potentiometer 603 and ao clocks DR-ί and DR-2 belong to a relay DR that contains additional bias resistors. Which is controlled by a monostable multivibrator 700 transistor 605 in parallel with capacitor 602. This includes low voltage maintenance transistors 701, 702 and associated circuitry. It is optionally triggered over the capacitor 602 in order to control its charging interval by briefly controlling the source 705. This means that the capacitor 602 can only be charged with the aid of the switching device 704 from the emitter when the transistor 605 in the non-transistor 701 is switched off. Signals to the accompanying state is. This enables the switching device 704 to be operated precisely, resulting from a control of the period of the astable waveform. Relay or a similar component can exist. The timing interval of oscillator 501 can be fed via line 114 F ,
30 Details of the receiver i 12 are set in Porm stand value of the potentiometer 603 as desired by changing the resistance. In ■ a simplified block diagram in FIG. 3 any practice can do this automatically by using shows. Signals of a resistor provided with taps and transmitted via the test circuit are carried out in a known manner on the circuit 126 as a function of relays. During the test carried out, either the test shutdown and protective effect tests, which are to be described later on receive input 126 A or the auxiliary receive, the time control input 1265 is available e.g. !guided. A line selector 301 oscillator 501 under control of a signal that separates the test reception input 126/4 from the auxiliary receiver 112 via line 115 and the re-reception input 126 B. Typically contains stand 606 is supplied. The potentiometer 603 is the line selector 301 coupling networks to keep these tests by actuating the adjustment of the receiver input impedance to the lais D or C (Fig. 5) and accordingly by opening telephone transmission lines. In practice, the contact 5D3 or . 5C3 ineffective. The function of the line selector, ie the feed

The monostable multivibrator 502 provides a generation of signals at the input 126/4 or 126 B.

typical execution. It contains the in a nor- line 302, using switchgear

paint transitions arranged in a monostable circuit, for example relays, in a known manner

sistors 610 and 611. A timing control of the multi-implemented. Call signals from line selector 301 ..

vibrators is controlled via a potentiometer 620, a via line 302 to the band-stop filter 303, in

Resistor 621 and a capacitor 622 are reached. which the frequency of 2100 Hz of the receiving

A transistor 625 ensures a short recovery time signal is suppressed. The filter 303 can be

of the multivibrator. The transistor 630 is known as an emitter 50. The oppression

foliar switched to improve a decoupling between the frequency of 2100 Hz

to enable the stages. The transistor 611 is for receiving the test signals. She doesn't have any more

normally switched on (conducting), and the tran- consequences, since this frequency does not relate to any information

Sector 610 is normally turned off (does not contain any of the checks performed. The

conductive). Accordingly, the signals filtered at the outputs 55 are transmitted to a detector 304

Signals 515 and 516 generated a logic "0" an amplifier 305 and a full wave rectifier

or »1«. The unstable interval of the Multivibra-306 is supplied. The rectification gives

gate 502, with the help of the potentiometer 620, a unidirectional signal for a detector 304,

to adjust. In practice, one with taps can see the details in FIG. S are shown and the

See resistor together with relay to this 60 will be explained later.

Purpose to be used. The multivibrator is triggered by the read input setting network 315 which is supplied by the oscillator 501 via the indicated signals via a smoothing filter 310 line 510. When fed to the monostable. These signals are proportional to the tactile multivibrator brought into its unstable state in relation to the received signals. If they are, a signal is supplied to transistor 605 via line 65 network 315 with predetermined reference signals vertung511, which causes transistor 605 to short-circuit the capacitor 602 that has been generated for the individual tests so that they are the ones. Details of the read input set-up network voltage across capacitor 602 are very small works 315 in FIG. 9 shown. The algae

The reading unit 320 is given the slight difference between the displayed signals and the reference signals fed, where it is determined whether the tested echo suppressor has passed the respective test or not. The reading sensitivity unit 325 ensures a sensitivity setting of the reading unit 320 accordingly the specific test carried out in each case. The sensitivity setting of the reading unit 320 with the aid of the unit 325 results in connection with the comparison of the received signals and the reference signals "good-bad" limit values generated by the read input setting unit 315 for the specific test carried out in each case. The Lesc sensitivity unit 325 can, for example and assuming the reading unit 320 is a voltmeter, a variety of shunt resistances exist, which are connected to the voltmeter to increase its sensitivity for the jcwi-iliucn to adjust exams as needed.

Fig. 8 shows the details of the detector ·, 304. As cistes is a Schmitt trigger 800 with transistors 801,802 and associated components are provided, which acts as a detector for the envelope of the received signal. The one delivered by the Schmitt trigger 800 Sign-'l is fed to e-netn integrator 810, the disturbance spike / s eliminated. The integrated signal goes to a second Schmitt trigger 820 with transistors 821, 822 and associated components in which the duty cycle of the envelope signal is determined will.

The signals generated by the Schmitt trigger 820 are proportional to the duty cycle of the received signal and are first an emitter follower transistor 830 and then an output line 309 fed.

Those at the emitter of transistor 830 (point 831) and at the collector of transistor 830 (point 832) Generated voltages are optionally via switching elements 840 or 841 a line 115 to Control of the transmitter 111 (Fig. 1) supplied during certain tests.

Details of the read input setting unit 315 are shown in FIG. In principle it is at the unit 315 a voltage comparison circuit with transistors 901 and 902. The mode of operation this circuit is easy to miss. That of the base of transistor 901 on the line 311 is a DC voltage that is proportional to the duty cycle of the received signal is. Reference signals are generated in the bias network 903 in a known manner and accordingly the respective test carried out optionally supplied to the base of the transistor 902. In the circuit according to FIG. 9 provides the connection between the collectors of transistors 901 and 901 902 at 904 effectively represents a current summing point. When applied to the bases of the transistors

901 and 902 are identical, no current flows accordingly to line 316. If, for example that of the bases of transistors 901 and

902 is not the same, a signal will be proportional to the difference between these signals via the line 316 to the reading unit 320 (Fig. 3). So there is no signal for the read connection 320 when the indicated signal applied to the setting unit 315 is equal to the reference signal.

4 shows the details of the feedback unit (loop-around unit) 150. The path 134 of the test line 130 is connected to the connections 401 of the feedback unit 150 in order to carry out the tests. In a corresponding manner, the path 144 of the auxiliary line 140 is connected to the connections 402. The paths 134 and 144 are connected via a transformer 403, the normally open contacts FI and FI of the relay F, the band-stop filter 4: (C and the transformer 411 and form part of the test loop. The path 133 of the test line 130 and

ίο the path 143 of the auxiliary line 140 are over the Transmitter 412 interconnected to complete the test loop. An oscillator 420, the one from the remote's milliwatt power supply

Office 101 provides a signal of predetermined frequency and amplitude on path 134 of test lead 130 which is used to calibrate the test equipment. At the beginning of the calibration process, the relay G is actuated for a predetermined interval to the output of the oscillator

so to short-circuit 420 with the help of its normally open contact GI. This gives certain pieces of equipment which may be located in the course of the line 134 the possibility of assuming a predetermined operating state. After completion of the calibration process to be described later, the oscillator 420 is switched off from the path 134 in a known manner by actuating the relay F.

Several types of echo suppressors used in telephone systems are encountered in the test. General In other words, these can be divided into two groups, namely "split" echo cancellers and "full" echo cancellers. Split echo cancellers are commonly used in transmission circuits are used with long delays and contain separate locking elements at each end the transmission path. The complete echo suppressors are generally used in transmission circuits with relatively small delays. stanchions used. Basically, they consist of two split locks at one end of the Transmission path. Full and split echo cancellers come in several forms known.

The different types of echo suppressors may have different parameters, their however, the functional operating properties must necessarily be similar. It was found, that any type of echo canceller used on a transmission path is satisfactory performing a variety of dynamic tests while on let evaluate.

The dynamic tests to be carried out relate to functional properties, for example the blocking effect, the break-in, the switching off (“disable”) and the protective effect ("Guard action"). In practice, two types of locking tests are carried out, namely in the non-activated and in the actuated state. During the non-activated mode of operation, the checked or the tested echo suppressors are evaluated as to whether they are oversensitive or not. at the actuated mode of operation properties are checked, which in the field of echo suppressors as "Odd" and "even" sensitivity as well as "post-action time" are known. In a similar way is the intrusion test into an unconfirmed and

15 16

operated mode of operation divided. Do not interfere with the not and 132 in the line 130. The two operated mode of operation in the course of the intrusion signals with 1000 and 2100 Hz go to the unit The test is the differential sensitivity of 150, where the signal is 2100 Hz through the band echo canceller rated When the working cut-off filter 410 (FIG. 4) is attenuated. Then run wisely in the course of the burglary test, the 5 becomes the second calibration signal with 1000 Hz and the ge-echo lock on an incorrect setting of the differential damped signal with 2100 Hz for path 134 and sensitivity as well as checked for a property, possibly to the recipient 112. Losses on the those in the field in question as "burglary auxiliary line 140 are replaced by a reinforcement after-effect time" is known. The shutdown test is the setting of the auxiliary amplifier 245 (Fig. 2) in case of failure are matched into a non-actuated and an actuated io, in such a way that the reading unit 320 Working method divided. These tests serve the same value as the displayed signal (Fig. 3) only to determine whether the switch-off feature is the one previously indicated during the first calibration step. and associated parameters of the echo canceller in ord- showed signal. In other words, the reinforcement are. The protective effect test determines is set so that the reception level of the whether the echo suppressor in the presence of 15 the transmission circuit including the auxiliary voice frequencies Filter any remaining information on the transmission line away from 144 and on the test path 134 leaves. gnals with 1000 Hz equal to that of the unit

The testing of echo locks in a telephone 150 only via the test path 134 transmitted signal line, for example the echo locks 131 and 132 is. After the two calibration steps have been completed, the echo blocker in the test line 130 can be evaluated in the test line 130 (FIG. 1), 20 is initiated by first occupying the main unit IiO. will. The other connecting lines of the Ver-Dics are made at the test field 120-1, for example by binding connection groups, to which cue lines 130 have a switch assigned to the control field 121-1 and 140 belong, can also be activated as desired. After occupancy of the main unit 110 to be checked. There is no need to recalibrate the control panel 1 * 1-1 for all other control 35 test equipment. If, however, an anfeldcr, namely 121-2 to 121- «its auxiliary line is selected in a known manner, the test must be blocked. This ensures continuous testing of equipment being recalibrated to ensure that losses on the telephone line or lines are compensated for by the new auxiliary line,
which are assigned to the control field, in the present case the control field 121-1, which is now assigned to the check of the echo blocker 131, which started first with 30 or 132 in which the main unit HO has occupied for main unit 110. the special test or tests,

After the main unit HO has been assigned, this is done via the control panel

remote exchange 101 is programmed via test line 130 under ver 121-1. For example, determined

application of the echo suppressor to be tested dei ^v Tmittlungsausrüstung 122-1 and the particular type the

a test code, the time associated with the test field 120-1 35 of the signal used. the

is selected in a known way. In this step, the place of use of the echo suppressor, i.e. its use on

Of the testing procedure, the line 130, with the near or far end, determines the routing

Feedback unit 150 connected. As other test signals above. That is, signals to check the

Give ι, the feedback unit 150 delivers a first close echo suppressor 131 can via the path 133

Calibration signals of predetermined amplitude and frequency, 40 are supplied while the same signals are used

namely 1000 Hz, which is via the path 134 of the test test of the remote echo suppressor 132 over the path

line 130 is transmitted to the main unit 110. 144 are transmitted. The one to be carried out in each case

There, the received calibration signal is used to determine the form of the test to be used

longer 112 fed where it is used to preset the signal.

Reading unit 320 (Fig. 3) by setting the reading 45 The blocking check, for example, of the "odd"

Sensitivity unit 325 is used, one side of the echo suppressor 131 (Fig. 1) is through-

to establish a predetermined reading setting. According to by selected test signals via the test

Completion of this first calibration step is the circuit according to FIG. 1 and optionally via the

remote office 101 via a second telephone line, echo suppressor 131 are transmitted. It will be

namely the auxiliary line 140, selected, with 50 according to a plurality of test signals in the transmitter

in turn the equipment 122-1 and a test Hl (Fig. 2) generated, namely a pulsating Si

The check code assigned to field 120-1 can be used. gnal of 100t) Hz, a monitoring signal of

As described above, paths 143 and 144 are 2750 Hz and a shutdown signal of 2100 Hz. This

the test line 140 via the feedback unit 150 test signals are generated when the non-

used 55 activated and activated blocking check connected to route 133 or 134 of line 130,

the. After the test circuit has been established, both locking tests are continuous

binding the line 130 to the line 140 will send signals of 1000, 2100 and 2750 Hz through the

a second calibration step carried out. Oscillators 201, 202 and 203 generated and the

Two test signals are generated in the transmitter 111 and are fed to gates 211, 212 and 213. The signal from

one of which has the same frequency as the 60 2100 Hz is also via the switching element 215

from feedback unit 150 is applied to auxiliary amplifier 245 during the first. It will be

Calibration step delivered signal, namely 1000 Hz, has to switch off the echo locks in the closing

and another signal at 7100 Hz. These signals use auxiliary line. The gates 211, 212 and 213

are controlled via the connection 125 (Fig. 1) to be controlled by signals from the control

Scndcwcg 144 given to auxiliary line 140. The 65 timing and timing unit 220 can be delivered

Signal with 2100Hz is used to switch off the echoes. Let it be briefly to F i p. 5 referred to. the

Block 141 and 142 used in the auxiliary line 140, relays A and B shown there are during the

so that when the echo locks are checked, it activates the blocking test in order to

17 18

To see through transmission of signals to the gates, for a correct function of the echo suppressor 131 only The output signal 516 of the monostable is then supplied when a "continuous over-multivibrator 502 of line 221, the signal of the wachungssignal is detected, causes a sub-source 530 of line 222 and ground of line broken waveform of Uber-223 fed. These signals and voltages are monitoring signals that the reading unit 320 is verden in a known way to control the gates tell the echo block 131 in this test to-211, 212 and 213 used. For example, the shows stops.

negative voltage supplied by source 530. The actuated locking test is performed using gate 212 in the non-conductive or off state. The same signals are used that were not used in the test, the ground potential supplied via line 223 was not used, and the gate 213 was kept in the on state. Thus, assuming that the amplitude of the pulsating gate 213 is a continuous signal corresponding to a signal of 1000 Hz is increased to a value, Fig. 10B. The signals generated at the output 516 of the mono or a predetermined amount greater than the stable multivibrator 502, which is the minimum operating value to which the class from gate 211 via line 221 applies, to which echo suppressor 131 applies are used to generate the pulsating signal Fig. IOC shows the signal with 1000 Hz, which is connected to the with 1000 H? corresponding to Fig. 10A. On this odd side of the echo suppressor 131 transmitted wi.d. Embodiment, the signal with 1000 Hz has a transmission delay r, which is at the pulse width of about 15 msec and a period transmission of the signal via path 144, which of eiv.a 200 msec. These intervals can result from feedback unit 150 and path 134 is indicated in Ab- for different types of echo suppressors. The influence on the monitoring signal depends on its individual parameters from 2750 Hz when the echo suppressor 131 responds, which is not important for an explanation of the present invention on the pulsating signal of 1000 Hz. The signals shown with 1000 Fig. IOD. As expected, the setting unit 225 is over- and 2750 Hz, the train monitoring signal is interrupted by an attenuation, where it is brought to predetermined amplitudes that are in the echo suppressor 131 on the even side. For the non-activated locking check, the assigned path is inserted when the signal sets the signal at 1000 Hz to a predetermined amplitude of 1000 Hz on the odd side of the echo suppressor, which is found to be smaller than that amplitude. When the sensitivity is on tude normally operating the echo lock. 30 on the odd side is too low, the over-the signal with 2750 Hz is also not interrupted on a prewatch signal, as there is no damping-specific amplitude that is inserted below the fung on the even side. The prescribed minimum operating level of the delay A shown in FIG. IOD lies between the checking echo suppressor. The pulsing signal applying the signal of 1000 Hz and the damping with 1000 Hz is given via the line selector 230 for 35 insertion is given as a so-called echo suppressor auxiliary amplifier 245 and the continuous response time is known. The V jr. Delay B in the down monitoring signal with 2750 Hz over the line switching the inserted attenuation after the end selector 230 to the test amplifier 240. According to the signal of 1000 Hz, the signals with 1000 and 2100 Hz are as echo lock lag over the operating time known. Accordingly, the signal fed to the Emp connection 125 to the transmission path 144 of the auxiliary line 40 catcher 112 according to FIG. 10E should contain a 140 (FIG. 1), and the monitoring signal with a signal with 2750 Hz, which is periodically transmitted for a 2750 Hz 133 of the test lead interval D is interrupted. This interval is supplied to 130. The signal with 2100 Hz switches off the same as the echo lock delay time plus the echo locks 141 and 142 in the auxiliary line 140. Duration (15 msec) of the 1000 Hz pulse minus it does not affect the echo locks 131 and 132, 45 the response time on the odd side of the echoda it by a predetermined amount through the lock. The limit values of the attenuation interval D band-stop filter 410 in the feedback unit 150 are predetermined and are thus attenuated in the receiver by selection (FIG. 4). Only the pulsing signal of a predetermined bias in the 1000 Hz read is transmitted on path 134 of line 130 input setting unit 315 (Fig. 9) and through and consequently to the odd side of echo suppressor 131 50 reading sensitivity setting in the unit. The monitoring signal with 2750 Hz 315 programs that the reading unit 320 (FIG. 3) runs through the part assigned to the transmission path 133 and indicates whether the interruption interval of the echo suppressor 131, which is usually referred to as the received monitoring signal of 2750 Hz "even" side referred to as. It is received within the predetermined limits,
Catcher 112 via the feedback unit 150 and the 55 Since the echo suppressor 131 is an on-receiving path 143 of the auxiliary line 140. If the odd side of the echo suppressor 131 is not oversensitive to the locking test on the even side in the manner described above, it is allowed to perform the 1000 Hz signal. Failure to determine a level, and the monitoring signal arrives at receiver 112 without interruption, door the sensitivity and the lag time. If on the even side, the odd side of the echo suppressor 131 can be used for rentiak sensitivity testing during a differential. If it is one-sensitive, the signal will be at 1000 Hz. Details of such a test will be presented later in, and the connection arriving at the receiver 112 will be described with the Ehibrech test. . Monitoring signal has interruptions, but with a complete echo suppressor, hangover time on the even side caused by an attenuation addition in the path associated with the straight 65 tests for sensitivity and the side of the barrier 131 can easily be passed through. Since dif * read unit 320 of the receiver 112 lead by, for example, only the over- (Fig. 3) is programmed so that they a display wachungssignal the auxiliary path 144 and the signal

19 " 20th

of 1000 Hz are fed to the test path 133. According to FIG. 2, the test required are different said, the signals from the oscillators 201, 202 and 203 for the sensitivity test The test signals used on the odd side are generated and with the aid of gates 211, 212 and 213. to carry out a sensitivity test and the switching elements 214 and 215 essentially the even side swapped. A lock check 5 borrowed in the same way as with the beder above remote echo lock also corresponds to the lock test described above. Accordingly The method described for the near - echo suppression is the signal of 2100 Hz via the switching 131, the only difference being the path element 215 to the auxiliary amplifier 245 and the meets, to which the respective signals are fed. Auxiliary line 140 (Fig. 1) given to the Echo-Bi Dhfüh kii

p, signal,

time and response time within usable limits amplitude to the test amplifier 240 via the

zen lie. Switching element 214 and the line selector 230. The

The main purpose of the intrusion test is to determine whether the differential sensitivity is energizing a signal supplied on line 114A during this test. Far from the tested echo suppressor within the pre- The in Fi g. The bias signal shown in Figure 11A runs within certain limits. Simply put, this is carried out via path 133 of test 130 for uiige testing, by optionally adding similar straight sides of echo suppressor 132 in order to start these test signals on both sides, that is to say the bearing lines and 20, an attenuation in path 134 A straight side, which is fed to the echo suppressor, is added, which is connected to the even side of the and it is determined which of these signals the echo suppressor 132 is associated with. The amplitude of aes preamble transmission via the echo canceller controls. In the input signal, a check of complete echo suppressors is accordingly distorted to a value which is sufficient to enable the echo suppressor 132 to insert attenuation on its even side neither on the odd nor on the even side to induce greatest effective energy. The monitoring signal from sit / t that the echo suppressor suppresses the signal applied to the other side at 2750 Hz via path 144 of the auxiliary line and accordingly "breaks in 140 via feedback unit 150 and breaks the path". Split echo suppressors cannot suppress signals applied to their 134 of the line 130 to the even side of the echo less straight side. 30 lock 132. As with lock check, the over-that is on the straight side of a split echo. The signal applied to the monitoring signal is continuous and has an Amplispcrre, however, the level of the echo suppressor 132 can be broken by the level of the echo suppressor 132 that is breached by the suppression introduced below the minimum response ethical barrier. The in Fig. 11 B if the amplitude of the monitoring signal shown with a dashed line on the straight side is sufficiently large for the signal placed. So there are generated in the same way as in the case of the Sperrpnifunq and both sides of a complete echo suppression and only should therefore not be described here. Fig. 11 B dio gen-each side of a split echo suppressor also shows the pulsating signal with 1000 Hz, checked with regard to the intrusion. In addition, in the same way as the pulsed, a measure for the generating signal with 1000 Hz for the locking test can be generated during this test. The only difference is related to gaining split echo suppressors. In addition to the amplitude as well as the period and the impulse check of the differential sensitivity, the signal is also outside the range. In the present embodiment, during the intrusion test, the pulse width and the area of the echo barriers are known "break-in-post-pulse period of the signal with 1000 Hz 150 or effective time" for those echo barriers that are un- 45 600 msec. These intervals will have speaking positions due to factors. The non-actuated determined, which relate to the checked echo locks and the actuated burglary test are thus carried out, in particular the burglary response time, in order to determine whether the differential and the burglar delay time.
sensitivity and the break-in after-effect time rieh- According to Fig. 6, the pulse width and tig are set. 50 pulse period of the pulsating signal of 1000 Hz

The burglar check, for example the remote one, by setting the potentiometers 6P3 and 620 Echo suppressor 132 (Fig. 1) is activated by a selective of the oscillator 501 and the monostable multi-programming the main unit 110 initiated. vibrators 502 are chosen in a known manner. At bc-Wie In the case of the above-described blocking test, the correct types of echo blocks, it is advisable to this is done at the control field 121-1 by either 55 also the monitoring signal together with the that of the test to be performed, the type of pulsating signal of 1000 Hz during the one-echo lock and to give the location of the echo lock break test a pulsating curve, speaking pushbuttons selected or a suitable. According to Fig. 5, this is done by pressing neter program strip or similar to the control field 121-1 of the relay £ and transferring the at output 516 is fed. 60 of the monostable multivibrator 502 generated

The test control signals used in the burglary test to line 223 via the Arbcits-

signals are generated in the transmitter ill. These signals contact E-I and the normally closed contact ö-l of the relay £

contain a continuous signal of 1000 Hz or B. The control signals then graze over the

a pulsing signal of 1000 Hz, an overhead line 223 to the gate 213 (Fig. 2). The

monitoring signal of 2750 Hz and a switch-off signal 65 gate 213 is synchronized with your gate 211

of 2100Hz. The temporal length of these signals is controlled so that the signal at 2750 Hz is the same

according to the tested echo blocker and pulse width and pulse period like the pulsating one

the test circuit used is selected in advance. Has a signal with 1000 Hz.

21 22

The non-active part of the burglar test becomes when the burglar differential sensitivity of the

with the pulsating signal of 1000 Hz through echo lock 132 is within usable values,

out, which is reduced to a predetermined amplitude, the reading unit 320 can fail in this

half the amplitude of the display on the odd side of the test when the break-in lag time

5 applied bias signal to echo suppressor 132 is not within acceptable limits.

1000 Hz is set. If these signals are sent to the break-in delay time it is

Echo lock 132 are applied, no signal is transmitted through a property that is intentionally locked in echo locks.

the reception path 134 of the line 130 is used to receive an appearance

Catcher 113 transmitted, provided that the differences that occur in the field of echo suppressors as

The potential sensitivity of the echo suppressor 132 is referred to in favor of "double talk". To avoid

its straight side is not too big. If the reception of possible speech mutilation intervals during

the sensitivity of the even side is too great, the double-talk interval breaks, the burglary state is

pulsating signal of 1000 Hz and goes to the d. H. the length of time during which the damping is off

Receiver 112. The failure of the transmission path assigned to an echo blocker is then indicated

shows that the reading unit 320 (FIG. 3) is switched off with the aid of FIG. 15, for a predetermined interval,

Read input setting unit 315 and the read / receive namely maintain the break-in delay time. The

The sensitivity unit 325 is preprogrammed in such a way that the break-in after-effect interval is determined by

such a failure in reception any- that in the receiver 112 according to FIG.

of a signal during this special test, those signals can be detected which the tested

indicates. 3 ° have overcome echo lock.

The actuated part of the intrusion test is carried out under As with previous tests, the use of the same signals as in the non-different functional units of the receiver 112 actuated part of the intrusion test (FIG. 3) is preprogrammed in such a way that it is received with the Exception that the amplitude of the pulsating signal according to FIG. HD is specially brought to a value from the 1000 Hz signal. The size of the useful time intervals will be greater than that for this signal by a predetermined amount by selectively adjusting the amplitude of the bias signal from 1000 Hz to the bias of the read input setting unit. Since the amplitude of the pulsating signal from the reading unit 320 applied to the straight side of the 315 (FIG. 9) and by setting the sensitive echo suppressor 132 in the sensitivity of 1000 Hz is now greater than the amplitude of the 3 « ^{1 unit} 325 elected. The delivered to the receiver 112 odd side of the echo suppressor 132 applied pre- signal contains corresponding to FIG. HD in addition to the voltage signal, the pulsating signal propagation delay e overcomes an interval F which is equal to the due to the bias in the even pulse width (150 msec) of the pulsating signal side of the echo suppressor 132 inserted attenuation. An of 1000 Hz, and an interval G, which is the same as that said, a break-in takes place if the break-in delay time is the tested echo suppressor. Differential sensitivity of the echo suppressor 132 rieh- Since the pulse width F is constant, this is set to be sensitive. In the case of many types of echo blockers, the signal is a direct measure of the burglary delay, the burglary immediately with the application of the signaling time.

The procedure described above enables the signals used in this test to be similar. With certain echo evaluation of the intrusion properties for the odd locks, however, the intrusion only occurs after one side of a distant echo lock. The check of a predetermined period of time. In explaining breaking properties of near-end echo cancellers or the present test method, it has been assumed that echo canceller 132 is one of a suitable program for the main unit type in which the break-in takes place immediately , such that the burglary test finds. signals the respective paths of test line 130

As already stated, test and auxiliary lines 140 will be fed during this.

Procedure in addition to the intrusion sensitivity also when using the telephone system tüi

the break-in delay time is determined. So if that is the specific use case it is necessary to have the

1000 Hz bias signal according to FIG. 11 A 50 Deactivate echo barriers in the telephony lines

as well as to make the monitoring signal of 2750 Hz and that or in any other way ineffective. the

pulsing signal of 1000 Hz corresponding to data transmission over telephone lines is here

Fig. HC are applied to the echo suppressor 132 , for a typical example. It is also important

responds to this in such a way that the pulsating signal and that the Echospei are not erroneous during one

consequently the monitoring signal which is switched off in the path 134 55 voice transmission. Accordingly

can overcome inserted damping. If these are not activated and activated shutdown tests

The pulsating signal and the monitoring signal are not sufficient to ensure trouble-free operation

break through, the differential sensitivity is carried out wisely.

Echo suppressor 132 in favor of its odd side to It is known that echo suppressors due to a;

large. On the other hand, when the pulsating signal and 60 signal of 2100 Hz are turned off, the ar

break the monitoring signal as expected, its odd or even side is applied. To the

if the echo suppressor 132 has effected this part of the test, either the transmit or the

passed in addition to the susceptibility to breakage. The receiving path is fed to a telephone line

! .cscctnhcil 320 (Fig. 3) then indicates that the over switch-off signal, that all nchospcrrcn in this line are wachungssignale are received. Reading will be put out of action. Similar to de]

However, unit 320 is programmed to break-in and check the test

shows whether the break-in after-effect of the echo blocker is quickly evaluated in an echo blocker

132 is within usable limits. Also that selectively a monitoring signal and a spczi

If

23 '24

this test signal can be transmitted via the echo suppressor and the auxiliary test line 140 and consequently to the odd side of the system. In the present example, the main single signal of 2750 Hz is generated in the transmitter 111 and supplied to the test line 130 with the aid of the control field 121-1 for the test transmission path 133. In the general sense of the near echo suppressor 131, this signal is continuous. However, for certain non-actuated and actuated cut-off characteristics types of echo suppressors, it is useful to have one programmed. With the non-activated switch-off pulsating monitoring signal of 2750 Hz to be checked, it is to be determined whether the echo block 131 is being used. This becomes ineffective in the transmitter 111 due to a switch-off signal that the speaking control of the gate 213 achieves and should normally not lead to a switch-off. »<> According to Fig. 5 signals for the control system. When the non-actuated shutdown of gates 211, 212 and 213 is initiated, the shutdown release unit 250 and 223 are fed to lines 221, 222. When the switch-off (Fig. 2) is not activated, it is energized to ensure that the relay D is energized for a preliminary test. If no signals are required to the echo-sicrendes signal of 2750 Hz for a pulse-determined period of time, the lock 131 is to be delivered so that it assumes a quiescent relay E also energized. In FIG. 12A, some of the signals on line 221 generated by the non-actuated shut-off brator 502 are shown at the output 515 of the multivi-signal. ^ en normally open contact DA of relay D supplied. If, in short, the non-actuated cut-off relay E is actuated, the tests at output 515 are carried out in that, for a predetermined ao generated signals, the normally open contact interval is also smaller than the interval that EI and normally closed contact BI on the line 223 is normally given to switch off the echo lock. A monitoring signal acts on the output 516 of the monostable multi-function. Signals generated by the straight side vibrators 502, which are complementary to the signals at the echo suppressor 131 and a switch-off signal at its output 515, are applied to the line straight side. The switch-off signal »5 line 222 via the normally open contact DI, the rest is followed by a blocking signal, which is also given to the odd contact AX, the rest contact CI and the rest Se ^: -e of the echo blocker. The locking signal is given contact Bl . If these signals, namely, should cause the echo suppressor to insert an attenuation in the switch-off signal of 2100 Hz, the blocking signal from its straight side associated path 1000 Hz and the monitoring signal of 2750 H ₇ . and thereby to block the monitoring signal. 30 are applied to the echo suppressor 131, this inserts a If the echo suppressor 131 is not in operation and attenuation on its straight side and does not suppress the monitoring signal, it has thus failed the monitoring signal under the previous test. suspension that the echo canceller 131 is working properly. On the other hand, if the echo suppressor 131 generates this test in the transmitter 111 (FIG. 2), signals used for the shutdown test are used. As with earlier 35 does not pass, cm continuous or also tests, a continuous switch-off signal, pulsating signal of 2750 Hz is received and sent from 2100 Hz to the auxiliary line 140, accordingly in the reading unit 320 of the receiver ^! The echo locks 141 and 142 are displayed in the ineffective lock 112.

"land to resound. In addition, for the shutdown To ensure that the non-operated shutdown

· - a pulsating switch-off signal of 2100 Hz 4 ° switching mechanism of the echo lock 131 is working

If necessary, the auxiliary line 140 is supplied. In which the transmitter 111 causes the receiver 112 to

This example will send this signal via the sequence of test signals again when

Ve ₂ 134 to the odd side of the echo to be checked - the received monitoring signal is not

<nerrel31 transferred. The pulsating signal of reaching is large. The echo suppressor 131 then has the

'100 Hz must therefore pass through the feedback unit 150 45 non-activated shutdown test. According to

mfen This contains, as already indicated above, Fig. 8 this feature by actuating the

η band source filter for 2100 Hz. Realized because of the damping switching element 841.

iiHiB this filter must the amplitude of the issued monitoring signal is insufficient, bc-

transmitted signal of 2100 Hz by a predetermined- the transistor 830 is in the non-conductive feed-

• nn! Tarar the required 50 stand and a voltage generated at point 832 are increased

Sef on the W _e ri34 is achieved. Accordingly, the transmitter 111 via the diode 833, the switching

icfcrt the oscillator 202 a signal of 2100 Hz element 841 and the line 115 is supplied. In the

to the gate 212 so that its duration from the 111 loads the via the line 115 from the receiver

The voltage supplied to the control unit and time control unit 220 catcher 112 in accordance with FIG. 6

Snm wild According to Fig. 12A, the pulse _{55 has} the capacitor 602 of the oscillator 501 over the

The signal of 2100 Hz which generates a predetermined Im timing resistor 606. When the echo

pulse width / which is smaller than the minimum width, do not block 131 the non-activated shutdown test

which is used to actuate the shutdown mechanism, a monitoring signal is received in the receiver

Fchmrvrre 131 is required. The pulsating signal 112 was detected and there was no voltage across the line

ν ^ ΓζΚζ is given to the path 144 deV auxiliary line 140 6o 115 to the transmitter 111, so that the Prüfunj

(F i ρ η via the amplitude setting unit 225, which is not repeated.

Leituneswähler 230 and the auxiliary amplifier 245 to- The actuated shutdown test should show whether the

ν leads Accordingly F i g. 12 A follows the signal from echo suppressor 131 correctly to a suitable AbscnaiJ 2 i> h ') Hz a pulsating signal from signal responds immediately. During this exam you will

ItHX) Hz As with predictive tests, the 65 minimum fall time of the defeat device is evaluated

pulsating signal of 1000 Hz in the transmitter ill through It is also determined whether the echo canceller

selective control of gate 211 is generated. That remains out of action after di? Shutdown ™ pulsating signal of ^ 1000 Hz also goes to the direction has been actuated. The actuated peel

25 26

The test is initiated by initially ensuring that it does not pass, a signal to the oscillator 501 (FIG. 5)

is that the tested echo suppressor is transmitted in the rest, the one repetition of the actuated

state. This is achieved by initiating the shutdown test.

checked echo suppressor for a predetermined interval Referring to FIG. 1, those shown in FIG. 12B

no signals are supplied. Another see the odd side signals of the echo canceller 131 above

tion that the tested echo suppressor is in the path 141, the feedback unit 150 u id the path

Idle state is caused by the 134 being fed. That during the interval M

Shutdown release unit 250 (FIG. 2) upon initiation delivered a signal at 2100 Hz

the activated shutdown test is activated. Effect after echo lock 131 . During the interval N

the first signal-free interval is given an abio no signals are applied to determine whether

switching signal for a predetermined interval at which the cut-off device drops out prematurely. While

odd side of the echo canceller. The switch-off signal of the interval O is used to determine whether the echo blocker

a second, signal-free interval follows. While 131 has been switched off and not switched off again

this second interval is the shutdown release - this state has come. When the echo canceller

property evaluated. After the second signal »5 131 has been switched off and in this state

free interval will be a shutdown signal and one remains, has the signal of 1000 Hz and the signal

Blocking signal to the odd side of the echo canceller of 2100 Hz has no effect on the echo canceller, and

to see if it continues to be fed to the echo suppressor 131 even side

Activity is. As with previous tests, the monitoring signal of 2750 Hz is received

if you agree to the reaction of the echo suppressor to the ao catcher 112 transfer to indicate that this

various test signals has been passed by evaluating one for testing. If on the other hand

even side of the tested echo suppressor did not transmit the echo suppressor 131 during the interval M

Monitoring signal. (Fig. 12B) has been turned off or during

12B shows signals which should have been released again when the interval N is actuated

Shutdown test can be used. The monitoring »5 the signal of 1000 Hz to a suppression of the

signal of 2750 Hz and the continuous down monitoring signal of 2750 Hz. this will

switching signal of 2100 Hz are not shown. The recipient 112 as failing this test

The curve shape shown is indicated in the transmitter 111 by.

Selective control of the gates 211, 212 and 213 with The protective effect is a feature of echo-aid generated by signals that lock in the control 30, the activation of the echo lock-off and time control unit 220 are formed. Switching device prevented as long as others measure F i g. 5 relays A and D are actuated via the echo blocking function for this test voice-frequency component. As with the other exams, it can be transferred. F i g. 13 shows signals that are actuated when the relay E is operated when a pulsating protection test is used. Shown monitoring signal of 2750 Hz is required. At 35 there is a switch-off signal of 2100 Hz and a locked relay A and D is accordingly the signal of 1000 Hz. As with previous tests, gate 211 is controlled by signals, and a monitoring signal of 2750 Hz is sent to gang 515 of the multivibrator 502 can be generated. straight side of the tested echo suppressor applied, at-The gate 212 is controlled by signals at the output 520, for example via the path 144 and the return in the astable multivibrator 503 and the 40 means 150 as well as the path 134 to the echo suppressor 132 gate 213 by ground potential, which is about the rest (Fig. 1). The signals with 2100 and 1000 Hz are contact EI and the normally closed contact BI comes. The one on the odd side of the echo suppressor 132 via the multivibrator 503 generates a signal which the inter-path 133 is fed to the test line 130. If the valle contains L and M , and the multivibrator 502 echo suppressor 132 is working properly, it must not have an unstable interval, which switch accordingly 45, and the monitoring signal of 2750 Hz Fig. 12B the sum of the intervals L, M and N becomes The reason for the blocking signal of 1000 Hz is maintained. The multivibrator 503 partially pushes through. This can be seen in the receiver 112, since no multivibrator is controlled 502, results in the continuous monitoring signal is detected waveform in Fig. 12B from a superimposition and hence no signal to the reader unit 320 is the nionostabilen interval and the unstable inter- 50, when the echo suppressor 132 turns off, that becomes valle. The resulting time sequence for which the monitoring signal is not suppressed and a continuous signal supplied to the echo blocker 131 is detected in the receiver 112 , signal thus looks as follows: No signal during so that a failure on the reading unit 320 indicated interval L, a signal of 2100 Hz while is showing. In order to ensure that the protection of the interval Af, no signal during the interval N 55 operating device of the echo suppressor 132 is working properly and that both a signal of 2100 Hz and a signal are working, the transmitter 111 is again under a control signal of 1000 Hz during the interval O. The control of the receiver 112. More precisely, the control interval signals N and Af are generated by the astable planning and time control unit 220 (FIG. 2) wire multivibrator 503. The interval N results from a signal in the detector 304 (FIG. 3) ) generated chip from the interaction between the multivibrator 60 influenced voltage

502 and the multivibrator 503. At the end of its corresponding to FIG. 8 is the control of the Sen

unstable interval, the monostable multiplier 111 switches through the receiver 112 by actuation

vibrator 502 from the astable multivibrator 503 , the switching element 840 reached. A tension too

whereby its output 520 assumes a predetermined charge of the time control circuit of the oscillator signal state that the gate 212 is switched on 65 tois 501 of the time control unit 220 at the point

holds The interval 0 is partly generated by the receiver 831 and the oscillator 501 only ^ when displayed

Catcher 112 determined As explained above, if a continuous monitoring signal trains the echo suppressor 131 this part of the shutdown test, which indicates a failure in this test

and allows transistor 830 (Fig. 8) to conduct. The test signals are therefore continuous when a The monitoring signal is sent out again in the receiver 112. This is shown in FIG. 13 by the dashed curve shape indicated. As with earlier tests, the protective effects test used test signals generated in the transmitter 111 and need not be explained in detail.

The embodiments described above concerned the testing of echo suppressors in telephone lines, namely connection ^ - and long-distance lines The device described and the described « However, methods can also be used to carry out laboratory tests of individual echo suppressors or to Use evaluation of echo suppressors in subscriber line.

For this purpose 3 sheets of drawings

7ΛΛ C

Claims (14)

Patent claims: 1. Arrangement for dynamic testing of echo suppressors with a device that one Echo suppressor supplies a test signal, and with a device that the response of the echo suppressor on the test signal, characterized in that that the device for supplying the test signal is a signal generator circuit (201, 202, 203) for generating a large number of test signals of different frequencies, that the output of the signal generator circuit leads via a plurality of switching devices (211 to 215) which can be actuated in predetermined combinations in order to feed combinations of test signals of different frequencies to an output circuit (125),
that the combinations are chosen so that at least one frequency is a monitoring frequency and one or more other frequencies are control frequencies, that a connecting device (122-1 to 122-n) is also provided which connects the output circuit (125) to the the transmission line (130) containing the echo suppressor (131, 132) to be tested can be operated optionally
that a control device (121-1 to 121-n, 113) is provided which selects a desired switch combination so that a certain test signal combination with a control signal of suitable amplitude and frequency for testing a certain switching function of the echo suppressor (z. B. actuated or not actuated, sensitivity, differential sensitivity under intrusion conditions in the actuated or non-actuated state, intrusion overhang time, etc.) is applied to the transmission line simultaneously with a monitoring signal,
and that the device for determining the response of the echo suppressor has a receiver (112) which can be connected to the transmission line or to another transmission line connected to it and which receives and detects signals at the monitoring frequency from the output of the echo suppressor, and a reading device connected to the output of the receiver (320) which, as a function of output signals from the receiver, indicates whether the response of the echo suppressor for the specific, tested function is within predetermined limits (FIGS. 1, 2 and 3). 2. Arrangement according to claim 1, characterized in that for controlling for the Signal generator circuit (201, 202, 203) existing switching devices (211, 212, 213) a control and timing unit (220) is provided, which in turn is controlled by the control device (121-1 to 121-n, 113) for the selection of the switch combination and of the receiver (112) is controlled (Figs. 1 and 2). 3. Arrangement according to claim 2, characterized in that that the receiver (112) has a detector (304) responsive to selected test signals, one containing a reference signal input Read input adjust network (315) for comparing the output of the detector with reference signals and connected to the output of this network, the reading device (320) (Figs. 1, 3, 8 and 9). 4. Arrangement according to one of the preceding claims, with a first and a second Transmission path, at least one of which contains an echo suppressor, characterized by a feedback circuit (150) which can be switched on with the aid of switching devices so that it connects the two ways to form a test loop (Fig. 1 and 4). 5. Arrangement according to one of the preceding claims, characterized by a delay device in the setting device, which allows the selective creation of the test signals by a delayed a predetermined time. 6. Method for dynamic testing of echo suppressors in a communication circuit mi ι a first and a second transmission path by means of an arrangement one of claims 1 to 5 by applying a test signal to an echo suppressor and detection the response of the tested echo suppressor to the test signal, characterized by the following procedural steps: a) connecting the first and second transmission path at the far end of the Transmission circuit; b) Generating AC test signals that have two or more signals different from each other Frequency included, of which at least one is a monitoring signal and the other or the other control signals represent; c) Applying a selected test signal to the other end of one of the transmission paths, the test signal being selected so that the echo lock control signals are used to test a specific switching function the echo lock (e.g. activated or not activated, sensitivity, differential sensitivity under intrusion conditions in the actuated or non-actuated state, burglary overhang time, etc.) suitable frequency and have amplitude; d) Receiving and detecting signals with the monitoring frequency, which from Exit the echo suppressor come and appear at the other end of the other transmission path to form a Output signal; e) Evaluating the output signal to generate a read signal that indicates whether the Response of the echo suppressor for the specific, tested function within a predetermined Limits. 7. The method according to claim 6, characterized by transmitting a test signal first Calibration signal from the far end via the one transmission path and then Transmission of a test signal as a second calibration signal via the first and second transmission path and adjusting the gain of the test arrangement such that the amplitude of the received both calibration signals is essentially the same to avoid losses on the transmission path to compensate for the evaluation of the transmitted test signals. 8. The method according to claim 6 or 7, characterized in that some of the test signals to the first circuit path of the echo suppressor and other test signals to the second circuit path of the echo suppressor. 9. The method according to claim 8, characterized in that a first test signal to the first circuit path for predetermined intervals to check the blocking effect of the echo canceller is applied and that a second test signal (monitoring signal) to the second Circuit path is applied, the amplitude of which is ao below the operating level of the echo suppressor is to monitor the response of the echo suppressor to the first test signal. 10. The method according to claim 9, characterized characterized in that a third test signal to one of the transmission paths for disconnection of all echo locks located therein is given. 11. The method according to claims to 10, characterized characterized in that a fourth test signal and a fifth test signal are essentially the the same frequency can be applied to the first or second circuit path of the echo suppressor, that the fifth test signal has a greater amplitude than the fourth test signal to the burglary property to test the echo suppressor, and that a sixth test signal with an amplitude below the operating level of the echo suppressor is supplied to monitor the response of the echo suppressor to the fourth and fifth test signals. 12. The method according to claims to 11, characterized characterized in that a seventh test signal to the first circuit path for an interval! is applied, which is smaller than the interval that is required to actuate the cut-off device the echo suppressor is necessary that eiu eighth test signal to the first circuit path for an interval is applied, which is normally sufficient to operate the locking device of the echo lock, and that a ninth test signal is given to the 5 = second circuit path to the Addresses the echo suppressor to monitor the seventh and eighth test signals. 13. The method according to claim 8 to 12, characterized in that a tenth test signal is applied to the first circuit path for a first and second predetermined interval, which are normally sufficient to actuate the switch-off device of the echo suppressor, that one eleventh test signal, which is normally sufficient to activate the locking device of the echo lock, is applied to this circuit path during the specified interval to determine whether the cut-off device remains actuated, and that a twelfth test signal with a Amplitude below the minimum operating level of the echo suppressor to the second circuit path is applied to the response of the echo suppressor to the tenth and eleventh test signals to monitor. 14. The method according to claim 12 or 13, characterized in that the seventh and eighth Test signal or the tenth and eleventh test signal on the grand of a predetermined state of the Echo suppression, which is determined by the ninth or twelfth test signal, is generated again will.