How does digital predistortion work?
Digital Pre-Distortion applies inverse distortion, using a pre-distorter, at the input signal of the PA to cancel the distortion generated by the power amplifier. This requires knowing the PA characteristics accurately with effective implementation for successful DPD functioning.
What is DPD in wireless?
Digital Pre-Distortion (DPD) is one of the most fundamental building blocks in wireless communication systems today. It is used to increase the efficiency of Power Amplifiers. A typical Class AB LDMOS Power Amplifier with WCDMA waveforms may have approximately 15-20% efficiency.
What is video bandwidth in power amplifier?
The video bandwidth (VBW) of an RF power amplifier is usually expressed as the frequency range over which the PA shows a symmetrical and constant intermodulation (IM) product.
What causes spectral regrowth?
Spectral regrowth is mainly caused by the most nonlinear component of the transmit chain, which is almost always the HPA.
What is RF envelope?
Envelope tracking (ET) describes an approach to radio frequency (RF) amplifier design in which the power supply voltage applied to the RF power amplifier is continuously adjusted to ensure that the amplifier is operating at peak efficiency for power required at each instant of transmission.
What is Doherty power amplifier?
The Doherty amplifier is a modified class B radio frequency amplifier invented by William H. Doherty of Bell Telephone Laboratories Inc in 1936. In this way, the amplifier achieves a high level of linearity while retaining good power efficiency.
What is DPD 5g?
Abstract. A novel digital predistortion (DPD) technique is proposed to linearize ultra-broadband millimeter wave (mmWave) power amplifiers (PAs) by only employing very limited bandwidth resources for the Tx, feedback loop (FB), and baseband (BB).
What is RBW and Vbw?
The bandwidth of that filter is called the resolution bandwidth, or RBW. Its bandwidth is called the video bandwidth, or VBW. The narrower the bandwidth, the less noise there is in the output signal, but again the narrower the bandwidth, the longer the sweep time.
What is a clipping function?
Clipping is a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability. Driving an amplifier into clipping may cause it to output power in excess of its power rating.
What is RF clipping?
Clipping is a form of distortion that limits a signal once it exceeds a threshold. Hard clipping results in many high-frequency harmonics; soft clipping results in fewer higher-order harmonics and intermodulation distortion components.