Transmitter and receiver for a wireless audio transmission system

• US 8,223,881 B2
• Filed: 10/27/2005
• Issued: 07/17/2012
• Est. Priority Date: 10/27/2004
• Status: Active Grant

• Current Assignee: Sennheiser Electronic GmbH & Company KG
• Original Assignee: Sennheiser Electronic GmbH & Company KG
• Inventors: Peissig, Juergen, Buhe, Gerrit, Meyer, Rolf
• Primary Examiner(s): Payne, David C.
• Assistant Examiner(s): Hassan, Sarah
• Application Number:
  US11/666,595
• Publication Number:
  US 20090046803A1
• Time in Patent Office: 2,455 Days
• Field of Search: 375/295, 348/485
• US Class Current: 375/295
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission H04B1/68 takes precedence

Abstract

There is provided a transmitter for a wireless audio transmission system comprising at least one analog/digital converter unit for analog/digital conversion of the analog audio signals to be transmitted, at least one digital signal processing unit with a compressing/encoding device for compressing and encoding the digitized signal to be transmitted, a digital/analog converter unit for digital/analog conversion of the digital output signals of the digital signal processing unit into analog signals, and a transmitting unit for wirelessly transmitting the output signals of the digital/analog converter unit. There is further provided a receiver for a wireless audio transmission system comprising a receiving unit for receiving wirelessly transmitted analog HF signals, an intermediate frequency unit for mixing the HF signals onto intermediate frequency signals, at least one analog/digital converter unit for analog/digital conversion of the wirelessly received signals, at least one digital signal processing unit with an expanding/decoding device for expanding and decoding the signals digitised by the at least one analog/digital converter unit, and at least one digital/analog converter unit for converting the digital output signals of the digital signal processing unit into analog signals.

Claims

1. A transmitter for a wireless audio transmission system comprising:

at least one analog/digital converter unit for analog/digital conversion of analog audio signals to be transmitted into a first digitized signal; and

at least one digital signal processing unit with a compressing/encoding means for compressing and encoding the first digitized signal into a second digitized signal to be transmitted, the compressing/encoding means comprising;

a filter bank for dividing the first digitized signal into different frequency bands;

at least one multiplier unit for multiplying the different frequency bands of the first digitized signal by weighting factors;

a sum filter bank for combining the output signals of the multiplication units to afford a filter bank total signal;

an addition unit for adding the first digitized signal to the filter bank total signal to obtain the second digitized signal;

a filter bank analysis unit for analyzing the second digitized signal; and

an envelope detection unit for estimating the envelope of the second digitized signal based on the analysis of the second digitized signal by the filter bank analysis unit to determine the weighting factors.

5. The transmitter according to claim 1, further comprising:

a transit time correction unit configured to subject the first digitized signal to transit time correction before reaching the addition unit.

6. The transmitter according to claim 1, further comprising:

a digital/analog converter unit for digital/analog conversion of the second digitized signals of the digital signal processing unit into analog signals; and

a transmitting unit for wirelessly transmitting the output signals of the digital/analog converter unit.

8. The transmitter according to claim 5, further comprising:

a digital/analog converter unit for digital/analog conversion of the second digitized signals of the digital signal processing unit into analog signals; and

a transmitting unit for wirelessly transmitting the output signals of the digital/analog converter unit.

2. A receiver for a wireless audio transmission system comprising:

a digital signal processing unit with an expanding/decoding means for expanding and decoding a received first digitized signal into a second digitized signal, the expanding/decoding means comprising;

a filter bank for dividing the second digitized signal into different frequency bands;

at least one multiplier unit for multiplying the different frequency bands of the second digitized signal by weighting factors;

a sum filter bank for combining the output signals of the multiplication units to afford a filter bank total signal;

an addition unit for subtracting the filter bank total signal from the first digitized signal to obtain the second digitized signal;

a filter bank analysis unit for analyzing the first digitized signal; and

an envelope detection unit for estimating the envelope of the first digitized signal based on the analysis of the first digitized signal by the filter bank analysis unit to determine the weighting factors.

9. The receiver according to claim 2, further comprising:

a receiving unit for receiving wirelessly transmitted analog high frequency signals;

an intermediate frequency unit for mixing the high frequency signals onto intermediate frequency signals;

an analog/digital converter unit for analog/digital conversion of the wirelessly received signals to obtain the first digitized signal for the digital signal processing unit.

3. A transmitter for a wireless audio transmission system comprising:

at least one analog/digital converter unit for analog/digital conversion of analog audio signals to be transmitted into a first digitized signal; and

at least one digital signal processing unit with a compressing/encoding means for compressing and encoding the first digitized signal to be transmitted into a second digitized signal, the compressing/encoding means comprising;

a time-variant filter unit for time-variant filtering of the first digitized signal;

an addition unit for adding the output signal of the time-variant filter unit to the first digitized signal to obtain the second digitized signal;

a spectral estimation unit for carrying out spectral estimation of the second digitized signal; and

a filter coefficient calculating unit for calculating the coefficients of the time-variant filter unit based on the spectral estimation of the spectral estimation unit.

7. The transmitter according to claim 3, further comprising:

a digital/analog converter unit for digital/analog conversion of the second digitized signals of the digital signal processing unit into analog signals; and

a transmitting unit for wirelessly transmitting the output signals of the digital/analog converter unit.

4. A receiver for a wireless audio transmission system comprising:

a digital signal processing unit with an expanding/decoding means for expanding and decoding a received first digitized signal into a second digitized signal, the expanding/decoding means comprising;

a time-variant filter unit for time-variant filtering of the second digitized signal;

an addition unit for subtracting the output signal of the time-variant filter unit from the first digitized signal to obtain the second digitized signal;

a spectral estimation unit for carrying out spectral estimation of the first digitized signal; and

a filter coefficient calculating unit for calculating the coefficients of the time-variant filter unit based on the spectral estimation of the spectral estimation unit.

10. The receiver according to claim 4, further comprising:

a receiving unit for receiving wirelessly transmitted analog high frequency signals;

an intermediate frequency unit for mixing the high frequency signals onto intermediate frequency signals;

an analog/digital converter unit for analog/digital conversion of the wirelessly received signals to obtain the first digitized signal for the digital signal processing unit.