DE3236194A1 - CORDLESS TELEPHONE - Google Patents

Description

G. Hofgen37

Cordless telephone set

The invention relates to a telephone set according to the preamble of claim 1.

Such a telephone set is from the article "A cordless infrared telephone" from E. Brown and S.-Schön, telcom report 3 (1980), issue 1, pages 24 bis 27, known. The carrier frequency for this telephone is Uses infrared light generated by pulse phase modulation transmits the digitized signals. The two-way transmission between the subscriber station and the The handset is carried out on a carrier frequency that according to the principle of Zeitrau 11iρ Iex transmission from both devices is being used.

The invention is based on the object of a telephony set of the type mentioned to indicate that with a single carrier frequency also in neighboring Telephone sets works and those in their entire Effective area has a constant transmission quality.

The solution to this problem takes place with the in claim 1 specified means. Further training can can be taken from the subclaims.

Z.T / P1-Wr / V

Sep 24, 1982 - 5 -

G. Hofgen 37

The new cordless telephone set works with a single carrier frequency that is also in neighboring Telephone sets can be used without Interference occurs between them. By the used Broadband transmission, there are no disruptive drops in field strength due to multipath effects.

The invention is explained below with reference to drawings an exemplary embodiment explained in more detail. Show it:

Fig. 1 ″ a block diagram of a telephone set with one fixed and one movable

Part;

2 shows the time sequence of the two-way transmission between the stationary and the movable part according to FIG. 1;

3 shows a block diagram of the transmitting / receiving parts

of the telephone set according to FIGS. 1 and

4 shows a diagram of the frequency-modulated carrier frequencies in the steady state.

In Fig. 1 is a long-distance speaking set based on a block diagram shown with a stationary part and a movable Ii chen part L 2. The other telephones of this type are in a telephone system constructed in the same way and therefore not shown.

An adapter 4 is connected to a subscriber line 3, in which those components are housed that are necessary to adapt the stationary part 1 to the

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G. Hofgen 37

Subscriber line are required, such as Hybrid circuit, selector contacts, etc. To the adapter 4 includes an encoder-decoder 5 (CODEC) and Interface 6, both of which are connected to a controller M. The control M is via three lines 7, 8, 9, connected to a transmitting / receiving part I S / E, to which an antenna 10 is connected. The control effects the processing of the coming and outgoing signals including intermediate storage and identification check and controls the process.

The movable part 2 has a receiver 11 and a microphone 12, which are connected to a controller S via an encoder-decoder 13 (CODEC). To the Control S is also connected to an alarm clock TA and a control unit 15 and it is available via three lines 16, 17, 18 in connection with a transmitting / receiving part S / E, to which an antenna 19 is connected. The control S works in a similar way to the M.

The call of an incoming call request on subscriber line 3 for the telephone with the fixed part 1 and the movable part 2 is from the adapter 3 given via a line R to the interface 6, in this converted into a digital call telegram, which from there via the control M and the line 7 to the Sending / receiving part I S / E reached. The sending / receiving part I S / E is modulated accordingly and the resulting signal is emitted by the antenna 10. The antenna 19 picks up this signal and the transmitting / receiving part I S / E converts this signal again and sends it via line 18 to controller S, which then sets alarm clock 14 actuated.

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The user can now use a button 20 in the operating part 15 a Ls replacement of the Gabe L function when picking up the handset actuate. When the button 20 is pressed, a Corresponding signal (telegram) to the stationary part 1 05 ", received there and sent by the controller M to the Interface 6 and given via a line G to the adapter 4, whereby the voice connection between the calling party Participants and the user of the telephone set ■ is established. ■

The language now passes from the adapter 4 to the Codieref decoder 5, where it is digitized, one being adaptive Delta modulation with 32 kbit / s is used, Via the controller M and the line 7, the digitized speech on the transmitting / receiving part S / E, from which a corresponding signal through the antenna 10 will be broadcast. The moving part 2 receives this signal with its antenna 19 and is there via the transmitting / receiving part S / E and the line 18 to the Control S and on to encoder-decoder 13, where the digitized language back into its analog form is converted so that it is reproduced in the listener 11 can be.

The speech recorded by the microphone 12 runs over the reverse route to subscriber line 3 and then to calling party. At the end of the conversation, the user presses key 20 again to replace the fork function when hanging up, whereby finally from the interface 6 via the line G of the adapter 4 for activation the subscriber line 3 is initiated.

Does the user of the telephone set want to use the fixed one Part 1 and the moving part 2 another Call subscribers of the telephone system, so press

G. Hofgen 37

he takes the key 20 and then a keypad 21 in the Control unit 15. The rest of the process is then as described, with the dialing signals being transmitted via a line W get from the interface 6 to the adapter 4.

To allow two-way transmission on one carrier frequency reach, is between the stationary part 1 and the movable part 2, an alternating transmission to provided according to the principle of time division multiplex transmission. For this purpose, a clock generator (not shown) is present in the controller M of the stationary part 1 whose help frame the necessary data and the Bittakjt is formed. The controller S in the moving part 2 is synchronized to this data frame and the bit clock.

The alternating time slots of the time division multiplex transmission are shown in Fig. 2, above the time axis t is the alternating sending and receiving of the stationary part 1, characterized by S1 or E1, and below the sending and receiving of the movable part 2, indicated by S2 and E2. A data telegram is sent in each transmission sub-slot S1 or S2 sent, consisting of 20 bits for the synchronization S, 20 bits for the identifier K, 10 bits for the preamble P and 206 bits for the message content 11N. A protection time of 10% is provided. at the planned digitization with 3 2 kbit / s results A time duration of 6.4 ms is then for the data frame. This results in a transmission speed of 90 kbit / s between the stationary part 1 and the moving part 2. Se h a f t in the operational state the transmitting / receiving parts S / E of the stationary Part 1 and the moving part 2 activated only for a short time

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G..Hofgen 37

to check the quality of the radio connection, whereby the power consumption can be reduced significantly. to For this purpose, the stationary ■■ part 1 sends at a distance of 128 data frames = 819.2 ms a checked telegram, the has the same structure as an OatenteLegram and contains a verification code instead of the message content. If the moving part 2 is working correctly, it will send back an acknowledgment telegram that the has the same structure as the test telegram and instead of the Message content contains an acknowledgment code. The operational readiness can be seen visually on the moving part displayed (not there LIt).

How it works when you switch it on for the first time or in the event of a malfunction is explained later.

In Fig. 3 are block diagrams of the transmitting / receiving parts S / E of the stationary part 1 and the movable Part 2 shown. Both the sending / receiving part are The same structure, so that only one is described. The following description applies to the stationary part sending and receiving movable part.

In the transmitting part is a microwave oscillator 23, whose Carrier frequency F is 37 GHz, and an oscillator for a wobble frequency fi available in the range from 1 to 10 MHz and a sawtooth Ver has run. The oscillator 24 is via line 8 from the control M adjustable to different values. The wobble frequency fi modulates the carrier frequency F in its frequency with a hub of 150 MHz and thus generates the spread carrier frequency to be transmitted, that of the digitized signals, that is the language that Calls etc. is modulated. The output of the microwave oven 23 is connected to a terminal a of a switch 25 connected, which sent it to the

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- 10 G.Höfgen 37
a terminal d connected antenna 10 connects.

The switch 25 has four connections a to d, between which, for example, diodes are arranged.

These diodes are set by the controller in such a way that

that in the transmission state the connections ad and bc and im

Reception status of the connections ab and cd each with each other are connected. The switch 25 can also consist of a Magic T.

The digitalized signals to be sent arrive via line 7 to switch 25 and control the Connection between the terminals ad such that a Amp Litudenta stung the spread carrier frequency F takes place.

Frequency shift keying can also be used as modulation will. In this case, the oscillator 24 is switched between two values by the digitized signals to be transmitted the wobble frequency switched back and forth that the Spread the carrier frequency. In the receiving part there is then a corresponding detector circuit for recovery of the transmitted signals.

In the receiving part, one input of a mixer M is connected to the connection c and the other input for the mixer oscillator is connected to the connection b. In the receiving state, the antenna 10 is connected to one input and the microwave oscillator 24 as a mixer oscillator to the other input of the mixer M. The intermediate frequency ZF mixed by the mixer M passes via a bandpass filter 26 and an amplifier 27 to a demodulator 28, which sends the demodulated signal to the line 18.

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-11-G.Höfgen 37

The bandpass filter 26 has a center frequency that corresponds to the hub of the Frequency modulation corresponds to the carrier frequency and so that is 150 MHz. The bandwidth is around 10 up to 15 MHz. The correlation of the micro-wave population Lator 23 generated carrier frequency F *, which as mixing frequency frequency is used with the received carrier frequency F from fixed part 1, requires a frequency locked loop. This frequency control loop consists of one Discriminator 29 and a controller Ri with an integral Behavior. The discriminator 29 is connected to the output of the Amplifier 27 is connected and, in the event of a deviation from the carrier center frequency, sends a corresponding signal to the subsequent controller Ri / which controls the oscillator 24 so that a correlation between the carrier frequencies F and F * and in the steady state State there is a time offset of half a period. Here then is the frequency difference between the carrier frequencies F and F * equal to the stroke, so 150 MHz. The IschLeife frequency excitement is therefore like that simple and reliable, because the wobble frequency fi has a sawtooth-shaped course.

At the sending / receiving part S / EE of the moving part 2 the same reference numerals are used for the same parts because of the same structure, only the The carrier frequency is called F *. The sending / receiving part of the stationary part Les 1 is in the sending position and that Sending / receiving part L of the moving part 2 is in Reception position shown.

In Fig. 4 the time course of the frequency modulus inert carrier frequencies F and F * is steady State of the frequency regulator I loop shown. From the

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G. Hofgen 37

time offset set by controller Ri from half a period between the carrier frequencies F and F * gives the difference of 150 MHz, which is equal to the stroke of the frequency modulation. From this it also follows that the intermediate frequency ZF output by the mixer M is equal to 150 MHz.

With the respective stationary part and the associated moving part is used for spreading Carrier frequency F or F * always the same wobble frequency fi used. Different WobbeIfrequenzen fi are used in neighboring telephones, so that the simultaneous operation even with overlapping Supply areas separated from each other and is possible without mutual interference. The respective wobble frequency fi is determined by the control M or S. a corresponding command is set to the relevant oscillator 24 via line 8 or 17, respectively.

The first time you switch on the telephone with the stationary part 1 and the movable part 2, it can happen that their WobbeIfrequenzen fi do not match. In this case, the stationary part 1 does not receive an acknowledgment telegram on its sent test telegram as a response and the receiving part of the movable part 2 remains constantly switched on because the time of the The arrival of telegrams from the stationary part 1 is still unknown. In the stationary part 1, the absence is triggered automatic forwarding of acknowledgment telegrams to another Wobbe I frequency fi. Then a test telegram is sent out again. This The search process is continued until the wobble frequency fi that corresponds to the movable part 2 is found. Then go to the fixed part 1

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G. Höfgen 3 7

and the movable part 2 in those already described State of operational readiness over.

When a moving part is also in the area of action of another stationary part arrived and thereby accidentally whose wobble frequency is set, can it incorrectly synchronizes itself to this wobble frequency. However, its control recognizes that the identifier does not match its own, which is a Switching to another wobble frequency fi triggers. The moving part remains at this wobble frequency. Since now the one belonging to the moving part Fixed part I no longer receives an acknowledgment telegram, he must in turn set the wobble frequency fi again of the moving part. This is done using the functions described under "Creation".

It can also happen that the stationary part is disturbed by a moving part that leads to another stationary part belongs and is set to the same wobble frequency. In this case it gives a commaηdo on its moving part to switch to another wobble frequency and then also turns to this new Wobbe Ifrequency.

When the moving part is out of range of its stationary part too far away, the Connection interrupted and appears on the moving part a corresponding signal (not shown). The stationary part I searches for the wobble frequencies fi one after the other away. After a certain number of searches turns off the stationary part for a certain Period from. After this period of time, the search process is repeated.

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This cycle is repeated until the connection is established be restored with the moving part can.

In the control part 15 there is a button 2 2 (FIG. 1), upon actuation of which the movable part is switched to a different wobble frequency. This switching triggers the automatic tracking of the new wobble frequency for the associated stationary part.
This function is provided in order to increase the quality of the connection again in the event of a deteriorating connection by selecting a new wobble frequency.

The shelf and the power supply were not shown. There are several possibilities for this which have no points of contact with the subject of the application to have.

L e r s e i t e

Claims (11)

STANDARD ELEKTRIK LORENZ AKTIENGESELLSCHAFT Stuttgart G. Höfgen 37 patent claims 1. Cord loose telephone set, consisting of a Fixed part without controls and one movable part Part with all controls between which the Signal transmission by means of alternately sent impulses Is groups that modulate a carrier frequency takes place, d a d ure h ge k en η ζ ei c h η e t, that the carrier frequency (F, F *) is wobbled with a constant stroke, that the wobble frequency (fi) is adjustable is and that the pulse groups of both parts (1, 2) the prefixed with the same identifier (K). 2. Telephone set according to claim 1, characterized in that that the wobble frequency (fi) in the fixed and in the movable part (1, 2) is the same. 3. Telephone set according to claim 1, characterized in that that the swept carrier frequency (F, F *) is sampled in its amplitude by the pulse groups. 4. Telephone according to claim 1, characterized in that that two Wobbeifrequenzen are available, between which switched by the pulse groups will. ZT / PI-Wr / V 09/24/1982 - 2 - - 2 G. Höfgen 37 5. Telephone set according to claim 1, characterized in that that the WobbeL frequency (fi) is sawtooth-shaped Has course. 6. telephony apparatus according to claim 2, characterized in that that in the fixed and in the movable part (1, 2) the receivers work on the superposition principle and that a frequency control loop in the respective receiver consists of a discriminator (29) and a controller (Ri) with integrating behavior. 7. Telephone according to claim b, characterized in that the difference frequency between the received and the locally generated carrier frequency in the steady state of the frequency loop is equal to the wobble and that the intermediate frequency (IF) generated in the receiver has the same value. 8. Telephone set according to claim 1, characterized in that that the wobble frequency (fi) of the stationary part (1) automatically changes to the wobble frequency (fi) of the moving part (2) adjusts. 9. Telephone according to claim 1, characterized in that that in the moving part (2) on receipt of a signal with a foreign identifier (K) automatically another wobble frequency (fi) is switched. 10. Telephone set according to claim 1, characterized in that that in the moving part (2) switching to another wobble frequency (fi) can be triggered manually is. - 3. G. Hofgen 37- 11. Telephone according to one of the preceding claims, characterized in that in the state of operational readiness creates t to reduce power consumption
the oscillation gates (23) for the carrier frequencies (F, F *) be switched on repeatedly only briefly and a test telegram from the stationary part (1) and as Reply an acknowledgment telegram from the moving part (2) is sent. 12, telephone set according to one of the preceding claims ^ characterized in that the carrier frequency (F, F *) in the micro wave range at about 37 GHz
lies.