EP0307377A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for avoiding spectrum spreading when switching a transmitter on and off
Assignee: Telefonaktiebolaget LM Ericsson AB
•
Filing: 1988-07-12
•
Granted: —
•
Expires: 2008-07-12
Abstract
Abstract An apparatus for avoiding spectrum spreading in switching on and off a transmitter in a station included in a time multiplexed radio transmission system, e.g. a mobile telephony system, where two mutually 90-degree phase-shifted baseband signals (sin a(t), cos a(t)) are generated, each of these signals being intended to modulate a carrier wave. The apparatus includes means (MP, DAP, DAI, DAQ) achieving that the power of the baseband signals follows an increasing reference level at the start of each time slot and follows a decreasing reference level at the end of each time slot.
Inventors
- 👤 Per Carl Meinolf Vollmer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 17:28
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/02; H04B1/04; H04B1/0475; G; G11; G11B; G11B20/00; G11B20/10; G11B20/12; G11B20/1215
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
139 words
Apparatus for avoiding spectrum spreading in switching on and off a transmitter in a station included in a time multiplexed radio transmission system, e.g. a mobile telephony system, two mutually 90-degree phase shifted baseband signals (sin a(t), cos a(t)) being generated, where each is intended to modulate a carrier wave, characterized in that the apparatus includes means (MP, DAP, DAI, DAQ) for controlling the power of the baseband signals (sin a(t), cos a(t)) such that the power of each of these during a given time period in the beginning of each time slot, which is assigned to the station and intended for transmission, at least practically follows an at least substantially increasing reference level, and, during a given time period at the end of each such time slot, at least practically follows an at least substantially decreasing reference level.
Claim 2
Dependent Claim
139 words
Apparatus for avoiding spectrum spreading in switching on and off a transmitter in a station included in a time multiplexed radio transmission system, e.g. a mobile telephony system, two mutually 90-degree phase shifted baseband signals (sin a(t), cos a(t)) being generated, where each is intended to modulate a carrier wave, characterized in that the apparatus includes means (MP, DAP, DAI, DAQ) for controlling the power of the baseband signals (sin a(t), cos a(t)) such that the power of each of these during a given time period in the beginning of each time slot, which is assigned to the station and intended for transmission, at least practically follows an at least substantially increasing reference level, and, during a given time period at the end of each such time slot, at least practically follows an at least substantially decreasing reference level.
Claim 3
Dependent Claim
112 words
Apparatus as claimed in claim 1, characterized in that the baseband signals (sin a(t), cos a(t)) are each generated in a table look-up memory (MI, MQ) and a digital-analogue converter (DAI, DAQ) associated with each memory, in that said increasing or decreasing reference level are generated in a further table look-up memory (MP) and a digital-analogue converter (DAP) associated with this memory and generating a control signal (c(t)), for controlling the gain of the baseband signals (sin a(t), cos a(t)) and in that a means (SL) for control logic is arranged to generate address signals to the memories (MI, MQ, MP) in response to an input data flow supplied to the apparatus.
Claim 4
Dependent Claim
46 words
Apparatus as claimed in claim 2, characterized in that the gain of the baseband signals (sin a(t), cos a(t)) is controlled by controlling the gain of the digital-analogue converters (DAI, DAQ) associated with the memories (MI, MQ) for generating the baseband signals (sin a(t), cos a(t)).
Claim 5
Dependent Claim
33 words
Apparatus as claimed in claims 2 and 3, characterized in that it also includes a regulating loop (E,K,S) for controlling the output power of the transmission in response to said control signal (c(t)).
References Cited (Backward Citations)
GB1470314A
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.