Hand-held transmitter for the emission of coded electromagnetic pulses, and a receiver for receiving pulses emitted by the transmitter

• US 4,878,052 A
• Filed: 02/05/1988
• Issued: 10/31/1989
• Est. Priority Date: 12/05/1987
• Status: Expired due to Fees

• Current Assignee: Alltronik Gesellschaft Fur Elektronische Steuerung und Antriebe mbH
• Original Assignee: Alltronik Gesellschaft Fur Elektronische Steuerung und Antriebe mbH
• Inventors: Schulze, Matthias
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Rudpod, E. O.
• Application Number:
  US07/152,883
• Time in Patent Office: 634 Days
• Field of Search: 340/825.69, 340/825.72, 340/825.71, 340/825.57, 340/825.62, 375/22, 375/23, 455/114, 455/63, 455/119-121, 455/353, 455/352, 455/355, 455/91, 341/176
• US Class Current: 340/12.22
• CPC Class Codes: G07C 2009/00206 the keyless data carrier being hand operated
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 19/28 using pulse code
• CPC Class Codes: H04B 1/034 Portable transmitters
• CPC Class Codes: H04B 1/202 by remote control

Abstract

The invention relates to a hand-held transmitter and a receiver tuned to e.g. for remote control of garage doors, the transmitter consisting of a current/voltage supply (100), a coding unit (200) generating coded electromagnetic pulses and with an adjustable code, a pulse shaper (300), an HF oscillator (400), an HF output stage (500), a filter (600) and an antenna (700). In order to simplify the construction of such a transmitter, it is suggested according to the invention that the oscillator (400) comprise a circuit which enables a reliable oscillation build-up pattern in a relatively wide range of frequencies around the rated frequency and that the filter (600) connected between the output stage (500) and the antenna (700) be a steeply flanked low-pass filter.

Claims

1. A hand-held transmitter for emitting coded electromagnetic pulses for reception and processing by a receiver tuned to said transmitter, preferably for the remote operation of garage doors, said transmitter comprising:

(a) a current/voltage supply having output means;

(b) a coded pulse generating coding unit with an adjustable code coupled to said output means of said current/voltage supply and having an output;

(c) a pulse shaper having an output and coupled to said output of said coding unit;

(d) an HF oscillator having an output and coupled to said current/voltage supply output means;

(e) an HF output stage having an output and coupled to said pulse shaper output and to said oscillator output;

(f) an antenna; and

(g) a filter coupled between said HF output stage and said antenna;

wherein said HF oscillator comprises a circuit which enables a reliable oscillation build-up pattern in a relatively wide range of frequencies around a rated frequency, and said filter is a steeply-flanked low-pass filter.

2. A transmitter according to claim 1, wherein the HF oscillator can be operated in the range from ±

10% of its rated frequency.

3. A transmitter according to claim 1, wherein the HF oscillator includes a quartz resonator, a transistor and an oscillator circuit comprising at least one capacitor and a coil.

4. A transmitter according to claim 1, wherein the antenna includes a trimming capacitor and in which the antenna is energised via a tapping.

5. A transmitter according to claim 1, wherein a capacitor is provided at the input of the antenna for impedance transformation.

6. A transmitter according to claim 1, wherein said output stage includes a transistor having a low potential terminal, said pulse shaper is a trapezoidal pulse shaper and its said output is connected to said low potential terminal of said output stage transistor.

7. A transmitter according to claim 1, wherein the low-pass filter has a flank steepness of at least 60 dB to the first harmonic.

8. A transmitter according to claim 1, wherein the coding unit comprises a microprocessor which has a selectable number of information bits selectively consisting of 12 or 22 bits.

9. A transmitter according to claim 8, wherein said coding unit includes a diode matrix circuit for setting a part of the code number.

10. A transmitter according to claim 8, wherein said coding unit further includes a coding bridge, said coding unit being adapted to trigger various functions which can be set via said coding bridge connected in the coding unit.

11. A transmitter according to claim 1, wherein the individual component elements are mounted on a wafer using the SMD (surface mounted device) technology.

12. A receiver for receiving coded electromagnetic pulses emitted by a transmitter according to claim 1, said receiver comprising:

(a) a current/voltage supply having output means;

(b) a high frequency receiver part having an output and coupled to said current/voltage supply output means and including;

(1) an HF antenna input circuit for receiving an incoming signal;

(2) an HF/IF amplifier and mixer part having output means and coupled to said receiver part ouput;

(3) an HF oscillator coupled to said amplifier and mixer part;

(4) a demodulator coupled to said output means of said amplifier and mixer part; and

(5) a signal amplitude control circuit and level converter having an output and coupled to said output means of said amplifier and mixer part;

(c) a decoding unit with a code selector circuit having an output and coupled to said output of said control circuit and level converter; and

(d) an input/output interface circuit coupled to said decoding unit output;

wherein the HF oscillator of the high frequency receiver part resonates in a wide frequency range and comprises a circuit which enables a reliable oscillation build-up pattern in a relatively wide range of frequencies around the rated frequency, and wherein the HF antenna circuit further comprises an antenna oscillator circuit which has a trimming capacitor, and wherein the incoming signal is output from the antenna oscillator circuit through a capacitive divider, the divider being taken to earth on the HF side of the antenna oscillator circuit via a capacitor.

13. A receiver according to claim 12, wherein a non-trimmable wide band pass filter is connected in the high frequency receiver part between the signal output from the HF/IF amplifier and mixer part and the demodulator.

14. A receiver according to claim 12, wherein the high frequency receiver part further includes a ceramic IF filter and a resistor connected between the output of the mixer part and the ceramic IF filter to adjust the working point of the HF/IF amplifier and mixer part.

15. A receiver according to claim 12, wherein the decoding unit comprises a microprocessor with an adjustable code.

16. A receiver according to claim 15, wherein the decoding unit further comprises a diode matrix circuit for adjusting the code.

17. A receiver according to claim 15, wherein the microprocessor is connected to a reset circuit for automatically restoring the decoding unit to normal operating condition in the event of interference pulses or programming errors.

18. A receiver according to claim 12, wherein the input/output circuit incorporates low voltage recognition means to detect low voltage output from the receiver.

19. A receiver according to claim 12, wherein the input/output circuit contains a power-on reset circuit.

20. A receiver according to claim 12, wherein the input/output circuit is constructed as an adaptor circuit including internal soldered bridges which are selectively bridges so that the adaptor circuit can function selectively as an alternating current input/output, a direct current input/output and as a potential free output in conjunction with the direct current or alternating current input.

21. A receiver according to claim 12, wherein the input/output circuit includes means for providing current limitation, means to provide reverse polarity protection for direct current outputs and also means to provide pulse duration limitation.

22. A receiver according to claim 12, wherein the individual component elements are mounted on a wafer using SMD technology.

23. A transmitter according to claim 1, and further comprising fixed capacitive means coupling the HF oscillator to the HF output stage.

24. A method for coding electromagnetic transmission pulses comprising the steps of:

providing a supply of current/voltage to a code generator, to an HF oscillator and to an HF output stage;

generating coded electromagnetic pulses with an adjustable code wherein by a time-based tripartition of the bit information of the transmitted code (pulse telegram), the proposition concerning logical significance ensues in accordance with the following precept, in that after a flank fall from high to low and a subsequent flank rise from low to high after one-third of the transmission preset for one bit, a logic zero is transmitted, but upon a subsequent flank rise from low to high after two-thirds of the transmission time preset for one bit, a logic one is transmitted, wherein a pulse telegram 26 bits long is used, consisting of a 22 bit information part followed by a synchronizing pause 4 bits long, consisting of a low signal and a flank transition from low to high after the second third of the fourth pause bit;

shaping the generated pulses;

applying the shaped pulses to an HF output stage to provide an output signal;

providing HF oscillations to the HF output stage;

filtering the output signals from the HF output stage; and

then

applying the filtered signals to an antenna for transmission therefrom;

the HF oscillator enables a reliable build-up pattern in a relatively wide range of frequencies around the rated frequency, the filter is a steeply-flanked low-pass filter connected between the HF output stage and the antenna.