发明授权
- 专利标题: Digital modulator with compensation and method therefor
- 专利标题(中): 数字调制器及其补偿方法
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申请号: US694004申请日: 1996-08-08
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公开(公告)号: US5930299A公开(公告)日: 1999-07-27
- 发明人: Louis Jay Vannatta , William P. Alberth, Jr. , Terrie L. Frane
- 申请人: Louis Jay Vannatta , William P. Alberth, Jr. , Terrie L. Frane
- 申请人地址: IL Schaumburg
- 专利权人: Motorola, Inc.
- 当前专利权人: Motorola, Inc.
- 当前专利权人地址: IL Schaumburg
- 主分类号: H04B1/04
- IPC分类号: H04B1/04 ; H04L27/20
摘要:
In a digital modulator with compensation, a digital bit stream from a microphone (705), a speech coder (706), and a channel encoder (707) is sent to an encoder (720) which translates the bits into I/Q digital pulses with phase shift keying. A symbol correlater (730) notes when predetermined target phase symbol sequences, which contribute to a high peak-to-average power ratio, enter the encoder. If a target symbol sequence is encountered, the correlater directs compensation amplifiers or compensation filters (734, 737) of the I/Q signals. Next, I/Q pulse shaping filters (764, 765) filter the I/Q pulses according to communication system specifications. The filtered I/Q signals are then sent to a quadrature modulator (790) for RF modulation. Compensation of target symbol sequences reduces the negative impact they have on peak-to-average power ratio and increases the efficiency of the power amplifier (795) which extends the battery life of a communication device (700).
公开/授权文献
- US5172121A System for automatic identification of rail cars 公开/授权日:1992-12-15
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