公开(公告)号：EP1368918B1

公开(公告)日：2015-03-18

申请号：EP02710014.8

申请日：2002-01-17

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar ,  SCHÄFER, Andreas

IPC分类号： H04L27/34 ,  H04H20/46

CPC分类号： H04L27/3405 ,  H04H20/46

公开(公告)号：EP1435160A1

公开(公告)日：2004-07-07

申请号：EP02769928.9

申请日：2002-09-07

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar

IPC分类号： H04L27/36 ,  H03F1/02

CPC分类号： H04L27/367 ,  H04L27/361

摘要： Digital transmission using existing amplitude modulation transmitters (AM) results in transmissions in undesired boundary zones. This results from the fact that the two signals, the A signal and the RF-P signal, formed from the digital modulation signal (I/Q signal), which are required for controlling the AM transmitter have bandwidths much larger than the separate branches, namely the A branch and the RF branch, and said two signals enter with a propagation time difference in the multiplier of the transmitter output stage. Known methods for equalizing propagation time, up to at least 0.3 microseconds, and for reducing bandwidth, for example by a hole in the vectogram of the I/Q signal around the point 0/0, do not allow to reduce sufficiently transmissions in boundary zones. The method, in accordance with the present invention, is based on the fact that the use of an adapted filter for the phase modulated RF-P signal enables to reduce distortions occurring as a result of band limitation and that transmissions in boundary zones can therefore be likewise reduced. The adapted filter is a Gaussian filter with linear phase route. But if it is directly introduced in the transmitter output stage, the filtered RF-P signal does not enable achievement of the objective since the amplitude variations would once more be interrupted as a result of the switched mode. Therefore the amplitude variations are detected by the derived RF-P signal after passing through the filter by an envelope phase detector and introduced as correction signal with the A signal in a multiplier used as an auxiliary in the A branch. The corrected A signal is then multiplied with the RF-P signal in the transmitter output stage.

公开(公告)号：EP1413075B1

公开(公告)日：2009-12-02

申请号：EP02727296.2

申请日：2002-04-10

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar

IPC分类号： H04H20/49

CPC分类号： H04H20/49

公开(公告)号：EP1368918A2

公开(公告)日：2003-12-10

申请号：EP02710014.8

申请日：2002-01-17

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar ,  SCHÄFER, Andreas

IPC分类号： H04H1/00 ,  H04L27/34

CPC分类号： H04L27/3405 ,  H04H20/46

摘要： The problem associated with digital transmission using existing AM transmitters is that the out-of-band emission that occurs must be reduced in order to comply with the ITU mask, as the shoulder distances that can be achieved by the AM transmitters are not sufficient for a satisfactory compensation. The signals that are required to control the AM transmitters, (amplitude signal and phase-modulated RF signal), are formed from the digital modulation signal by a Cartesian → polar transformation, whereby the bandwidth for the amplitude signal and RF signal reaches a value, which causes an unacceptable out-of-band emission. To prevent this, the invention provides methods for digital modulation, which avoid the zero point by a wide margin in their vector diagram representations, i.e. which form a 'hole' around the 0/0 point. Modulation methods of this type are referred to as offset modulations and coded modulations. A variant of 16APSK is particularly suitable, as a higher net data throughput can be achieved with only 16 set points and negligible error protection coding is required. To transmit an OFDM signal, the 'hole' in the vector diagram is obtained by offsetting the zero crossings for the I(t) and Q(t) signals and the latter is achieved by the insertion of a pulse into the subsequent component, e.g. I(t), if the other component Q(t) already falls short of a defined threshold value. A BPSK test sequence for measuring the radio channel can be used by means a modification, in which a modulation signal is formed by inserting a pulse between two pulses with a change of sign bit, said modulation signal having a 'hole' around the 0/0 point. The size of the hole can be adjusted by the inserted pulse.

公开(公告)号：EP1413108B1

公开(公告)日：2008-01-02

申请号：EP02727297.0

申请日：2002-04-10

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar

IPC分类号： H04L27/00

CPC分类号： H04B1/0475 ,  H03F1/3241 ,  H03F2200/393 ,  H04B2001/0425

摘要： During a digital transmission with AM transmitters non-linear distortions occur also in the RF branch due to the band limitation in the amplitude branch, said distortions leading to undesired interference radiation. ITU requirements call for a constant curve of amplitude and phase response or propagation time in the amplitude branch as well as in the RF branch and for an equalization of the propagation time difference between the two branches. The required bandwith can be achieved in the RF branch by suitably selecting the quality of the oscillating circuits. In order to compensate for the non-linearities in the amplitude branch, a pre-equalization with inverse transmit function is used. According to an embodiment of the invention, the amplitude and propagation times are measured and stored. The transmit function is determined for the equalization network by inverse Fourier transform of the measured values. The network is connected in series upstream of the amplitude branch. As far as the propagation times of the amplitude branch and the RF branch are constant, the propagation time difference can be equalized by delaying the signal having the shorter propagation time in a digital modulator. The equalization of the non-linearities by pre-equalization with inverse transmit function can also be made for the RF branch.

公开(公告)号：EP1173940B1

公开(公告)日：2005-12-14

申请号：EP00917059.8

申请日：2000-04-07

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar

IPC分类号： H04H1/00 ,  H04B7/005

CPC分类号： H04L27/3488 ,  H04B17/309 ,  H04B17/382 ,  H04H20/12

公开(公告)号：EP0944973B1

公开(公告)日：2004-12-29

申请号：EP97948858.2

申请日：1997-11-03

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar ,  HÖRLLE, Christian ,  SCHÄFER, Andreas

IPC分类号： H04L1/24 ,  H04B1/12

CPC分类号： H04B1/123 ,  H04L1/241 ,  H04L1/242

摘要： The invention relates to a method for transmitting digital signals, especially in AM bands (radio broadcast bands). A high level modulation, preferably 32 ASPK or 64 ASPK is used for data blocks which are to be transmitted. The invention is characterized by periodic measurement of interference at the receiver end and the subtraction of thus determined interference signals from reception signals.

公开(公告)号：EP0944973A1

公开(公告)日：1999-09-29

申请号：EP97948858.0

申请日：1997-11-03

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar ,  HÖRLLE, Christian ,  SCHÄFER, Andreas

IPC分类号： H04L27 ,  H04B1 ,  H04L1

CPC分类号： H04B1/123 ,  H04L1/241 ,  H04L1/242

摘要： The invention relates to a method for transmitting digital signals, especially in AM bands (radio broadcast bands). A high level modulation, preferably 32 ASPK or 64 ASPK is used for data blocks which are to be transmitted. The invention is characterized by periodic measurement of interference at the receiver end and the subtraction of thus determined interference signals from reception signals.

公开(公告)号：EP1435160B1

公开(公告)日：2007-12-12

申请号：EP02769928.9

申请日：2002-09-07

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar

IPC分类号： H04L27/36 ,  H03F1/02

CPC分类号： H04L27/367 ,  H04L27/361

摘要： Digital transmission using existing amplitude modulation transmitters (AM) results in transmissions in undesired boundary zones. This results from the fact that the two signals, the A signal and the RF-P signal, formed from the digital modulation signal (I/Q signal), which are required for controlling the AM transmitter have bandwidths much larger than the separate branches, namely the A branch and the RF branch, and said two signals enter with a propagation time difference in the multiplier of the transmitter output stage. Known methods for equalizing propagation time, up to at least 0.3 microseconds, and for reducing bandwidth, for example by a hole in the vectogram of the I/Q signal around the point 0/0, do not allow to reduce sufficiently transmissions in boundary zones. The method, in accordance with the present invention, is based on the fact that the use of an adapted filter for the phase modulated RF-P signal enables to reduce distortions occurring as a result of band limitation and that transmissions in boundary zones can therefore be likewise reduced. The adapted filter is a Gaussian filter with linear phase route. But if it is directly introduced in the transmitter output stage, the filtered RF-P signal does not enable achievement of the objective since the amplitude variations would once more be interrupted as a result of the switched mode. Therefore the amplitude variations are detected by the derived RF-P signal after passing through the filter by an envelope phase detector and introduced as correction signal with the A signal in a multiplier used as an auxiliary in the A branch. The corrected A signal is then multiplied with the RF-P signal in the transmitter output stage.

公开(公告)号：EP1413108A2

公开(公告)日：2004-04-28

申请号：EP02727297.0

申请日：2002-04-10

申请人： Deutsche Telekom AG

发明人： RUDOLPH, Dietmar

IPC分类号： H04L27/00

CPC分类号： H04B1/0475 ,  H03F1/3241 ,  H03F2200/393 ,  H04B2001/0425

摘要： During a digital transmission with AM transmitters non-linear distortions occur also in the RF branch due to the band limitation in the amplitude branch, said distortions leading to undesired interference radiation. ITU requirements call for a constant curve of amplitude and phase response or propagation time in the amplitude branch as well as in the RF branch and for an equalization of the propagation time difference between the two branches. The required bandwith can be achieved in the RF branch by suitably selecting the quality of the oscillating circuits. In order to compensate for the non-linearities in the amplitude branch, a pre-equalization with inverse transmit function is used. According to an embodiment of the invention, the amplitude and propagation times are measured and stored. The transmit function is determined for the equalization network by inverse Fourier transform of the measured values. The network is connected in series upstream of the amplitude branch. As far as the propagation times of the amplitude branch and the RF branch are constant, the propagation time difference can be equalized by delaying the signal having the shorter propagation time in a digital modulator. The equalization of the non-linearities by pre-equalization with inverse transmit function can also be made for the RF branch.