Digital modem

• US 20020067764A1
• Filed: 09/14/2001
• Published: 06/06/2002
• Est. Priority Date: 09/20/2000
• Status: Active Grant

• Current Assignee: Maxlinear Incorporated
• Original Assignee: Infineon Technologies AG
• Inventors: Clausen, Axel, Harteneck, Moritz, Kindler, Matthias
• Granted Patent: US 7,006,560 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4263 involving specific tuning arrangements, e.g. two tuners
• CPC Class Codes: H04N 21/42676 for modulating an analogue carrier signal to encode digital information or demodulating it to decode digital information, e.g. ADSL or cable modem
• CPC Class Codes: H04N 21/437 Interfacing the upstream path of the transmission network, e.g. for transmitting client requests to a VOD server flow control in data networks H04L47/10; streaming protocols, e.g. RTP or RTCP, H04L65/65; scheduling or organising the servicing of application requests in data packet switching networks H04L67/60
• CPC Class Codes: H04N 5/455 Demodulation-circuits
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

Digital modem for data exchange between a data distribution unit (2) and at least one receiver (3, 4) which can be connected to the digital modem (1) with: a user-data forward signal path (17) for the transmission of user data from the television-data distribution unit (2) to the receiver (3, 4) over broadband user-data forward transmission channels,

a backward signal path (42) for the transmission of television-receiver control data from the receiver (3, 4) to the data distribution unit (2) over narrowband backward transmission channels;

and with a control-data forward signal path (27) for the transmission of narrowband control data or user data from the data distribution unit (2) to the receiver (3, 4) over narrowband forward transmission channels,

it additionally being possible for broadband user data to be transmitted over the control-data forward signal path (27) from the data distribution unit (2) to the receiver (3, 4).

Claims

1. A digital modem for data exchange between a distribution unit (2) and at least one receiver (3, 4) which can be connected to the digital modem (1) with;

a user-data forward signal path (17) for the transmission of broadband user data from the data distribution unit (2) to the receiver (3, 4) over broadband user-data forward transmission channels,

a backward signal path (42) for the transmission of receiver data from the receiver (3, 4) to the data distribution unit (2) over narrowband backward transmission channels;

and with a control-data forward signal path (27) for the transmission of control data and narrowband user data from the data distribution unit (2) to the receiver (3, 4) over narrowband forward transmission channels,

broadband user data additionally being transmitted over the control-data forward signal path (27) from the data distribution unit (2) to the receiver (3, 4).

2. The digital modem as claimed in claim 1, wherein the control-data forward signal path (27) has an analog input stage (28) for the reception of QPSK-modulated narrowband control data or narrowband user data and QAM-modulated broadband user data via a data transmission link (5) and a QAM/QPSK demodulator (30), which in a first operating mode demodulates the QPSK-modulated narrowband control data or narrowband user data and in a second operating mode demodulates the QAM-modulated broadband user data and sends the demodulated data to a control-data decoder (37) for the decoding of the demodulated narrowband control and user data and to a user-data decoder (35), connected in parallel with said control-data decoder, for the decoding of the demodulated broadband user data.

3. The digital modem as claimed in claim 1 or 2, wherein the QAM/QPSK demodulator can be switched over between the first operating mode and the second operating mode.

4. The digital modem as claimed in one of the preceding claims, wherein the QAM/QPSK demodulator has a synchronizing circuit for the synchronization to the received demodulated analog data signal and an echo-compensation circuit.

5. The digital modem as claimed in one of the preceding claims, wherein the user-data forward signal path (17) has an analog receiving circuit (18) for the reception of the QAM-modulated user data transmitted from the data distribution unit (2) via a data transmission link (5),

a QAM demodulator (20) for the demodulation of the QAM-modulated user data, and

a decoding circuit (22) for the decoding of the demodulated user data.

6. The digital modem as claimed in one of the preceding claims, wherein the backward signal path (42) has

a coding circuit (45) for the coding of the receiver data transmitted from the receiver (3, 4),

a QPSK modulator (47) for the QPSK modulation of the coded receiver data, and

an analog output circuit (49) for the sending of the QPSK-modulated receiver data to the data distribution unit (2) via the data transmission link (5).

7. The digital modem as claimed in one of the preceding claims, wherein the digital modem is a digital DVB modem.

8. The digital modem as claimed in one of the preceding claims, wherein the data transmission link (5) is a broadband signal cable, a satellite transmission link or a radio signal transmission link.

9. The digital modem as claimed in one of the preceding claims, wherein the control data decoder (37) of the control-data forward signal path (27) has an output terminal (158), which is connected to a MAC control circuit (56).

10. The digital modem as claimed in one of the preceding claims, wherein the user data, decoder (35) of the control-data forward signal path (27) has a signal output terminal (170), which is connected to the MAC control circuit (56) and is connected to a receiver terminal (77).