Transmission of data by ultrasound

• US 6,950,681 B2
• Filed: 12/29/2000
• Issued: 09/27/2005
• Est. Priority Date: 06/29/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Siemens AG
• Inventors: Hofmann, Ludwig
• Primary Examiner(s): Perez-Gutierrez, Rafael
• Assistant Examiner(s): Iqbal, Khawar
• Application Number:
  US09/751,959
• Publication Number:
  US 20010005176A1
• Time in Patent Office: 1,733 Days
• Field of Search: 455/569.1, 455/74.1, 455/73, 455/550.1, 455/552.1, 455/557, 455/566, 455/550, 455/552, 455/567, 341/155, 375/130, 375/140, 375/146, 375/147, 370/342, 370/441, 370/320, 370/335, 370/352
• US Class Current: 455/569.1
• CPC Class Codes: H04B 11/00 Transmission systems employing sonic, ultrasonic or infrasonic waves
• CPC Class Codes: H04M 1/6066 including a wireless connection

Abstract

An ultrasonic transmission system in which, for the purpose of transmission, a signal is used which generates a broadband signal by means of code spreading and is capable of eliminating any echoes by means of correlation. The transmission system exhibits a transmitter and a receiver. In this configuration, digital information is spread to a great bandwidth in accordance with a CDMA technique, D/A converted and then transmitted by means of ultrasound via an air Preferred applications of the present invention are air interfaces having a length of a few meters. One field of application is, for example, the connection of cordless handsets or hands-free telephones to telephones.

Claims

1. A method for transmitting voice data between a head part and a base part of a hands-free telephone, which comprises:

compressing information, being the voice data, to be transmitted using compression coding;

digitizing the compressed information;

spreading the digitized information over a wider frequency band using a CDMA technique;

performing a digital to analog conversion on the spread digitized information;

converting the digital to analog converted spread information into an ultrasound signal;

transmitting the ultrasound signal via an air interface;

at a receiver component, receiving the transmitted ultrasound signal and converting the received ultrasonic signal into an analog electrical signal;

performing an analog to digital conversion on the analog electrical signal;

despreading the analog to digital converted signal using a CDMA technique; and

decoding the despread analog to digital converted signal.

2. The method according to claim 1, which comprises reducing an effective bit rate of the information to be transmitted to about 1-10 kbit/s when performing the compression coding.

3. The method according to claim 1, wherein in performing the step of transmitting the ultrasound signal, the ultrasound signal is transmitted at a frequency between 200 and 400 kHz.

4. The method according to claim 1, wherein in performing the step of spreading the digitized information, the digitized information is spread to ±

100 kHz.

5. A hands-free telephone comprising an ultrasonic transmission system including:

a compression coder for compression coding analog information;

wherein the analog information is voice data;

a CDMA spreader for spreading digital information, which is obtained from said coded analog information, to a number of carrier frequencies using a CDMA technique;

a digital to analog converter for digital to analog converting the spread information;

an ultrasonic transducer for converting the digital to analog converted spread information into an ultrasound signal and for transmitting the ultrasound signal over an air interface; and

a receiver including;

an ultrasonic transducer for receiving the transmitted ultrasound signal and for converting the received ultrasonic signal into an electrical signal;

an analog to digital converter for analog to digital converting the electrical signal; and

a CDMA despreader for despreading the analog to digital converted signal using a CDMA technique.

6. The hands-free telephone according to claim 5, wherein said compression coder reduces an effective bit rate to about 1-10 kbit/s.