High-speed signal adjustment technology
As data rates increase, high-speed signals face significant challenges due to the skin effect and dielectric loss in transmission lines. These factors cause signal degradation during transmission, leading to distorted waveforms at the receiver end. To restore signal quality, various compensation techniques are employed, such as pre-emphasis, de-emphasis, and equalization. Before diving into these methods, it’s essential to understand the underlying causes of signal distortion.
The impact of high-speed serial link systems on signals
When a signal travels through a passive channel, its integrity is compromised by multiple factors, including insertion loss, impedance mismatch, crosstalk, and noise. These issues reduce the signal-to-noise ratio (SNR), potentially leading to bit errors (BER). Additionally, other sources like ringing, EMI, ground bounce, power supply noise, thermal noise, and environmental changes further degrade signal quality.
Skin Effect:
The skin effect occurs when alternating current (AC) flows through a conductor. Due to electromagnetic induction, the current tends to concentrate near the surface of the conductor, increasing the effective resistance. This effect becomes more pronounced at higher frequencies, effectively reducing the conductor's cross-sectional area and increasing resistance.
Dielectric Loss:
Dielectric loss arises from energy dissipation within the insulating material of a transmission line under an electric field. It is characterized by the dielectric loss angle and its tangent, known as the loss factor. This loss is especially significant in high-frequency applications.
In high-speed signal transmission, the high-frequency components of the signal experience greater attenuation than the low-frequency ones, making the transmission line behave like a low-pass filter. This behavior can be visualized in the following diagram.
On-chip solution - Equalization Technology
Equalization is a critical technique used to counteract signal distortion. It is typically implemented at the receiver side and functions as a high-pass filter to compensate for the low-pass characteristics of the transmission medium.
Pre-emphasis:
Pre-emphasis enhances the high-frequency components of a signal at the transmitter before it is sent over the channel. Since high-frequency components are more susceptible to loss, this technique helps maintain signal integrity. The rising and falling edges of the signal are emphasized to improve overall waveform quality.
De-emphasis:
Unlike pre-emphasis, de-emphasis reduces the amplitude of the signal in regions other than the rising and falling edges. This approach results in lower power consumption and reduced electromagnetic interference (EMI) but may lead to a smaller eye diagram height.
Equalizers:
Equalizers are used to mitigate the limitations of pre-emphasis and de-emphasis, especially in cases where crosstalk is present. They act as high-pass filters and are often implemented using adaptive algorithms that adjust based on the actual transmitted signal. This allows them to dynamically respond to channel variations and provide better distortion compensation.
Feedforward Equalizer (FFE):
FFEs use digital or analog filters to reduce intersymbol interference (ISI). While they are effective, they can introduce noise and require careful design to balance performance with power consumption.
Analog FIR Filter:
Analog FIR filters offer low power consumption and high-speed operation, making them suitable for on-chip integration. They avoid the need for high-speed ADCs and are commonly used in high-speed serial links.
Continuous-Time Filters:
These filters eliminate the need for sampling circuits, allowing for faster operation without the limitations imposed by sample-and-hold circuits.
Decision Feedback Equalizer (DFE):
DFEs are particularly effective in channels with deep spectral zeros. By using feedback, they can suppress noise and reduce ISI more efficiently than linear equalizers. However, they are prone to error propagation if early decisions are incorrect.
Eye Diagram:
An eye diagram is a visual representation of a signal's quality, obtained by overlaying multiple signal transitions on an oscilloscope. It provides insights into signal integrity, noise levels, and timing jitter. A well-formed eye diagram indicates good signal quality, while a closed or distorted eye suggests issues like crosstalk, noise, or poor equalization.
The eye diagram is a powerful tool for analyzing and optimizing high-speed communication systems. It helps engineers evaluate signal performance and fine-tune system parameters for optimal operation.
Tier 1 Solar Panel
Chinese Tier 1 brand Solar Panel (Longi, Jinko, Trina, Canadian, Ja etc.)
This type of product is mainly Tier 1 solar module product in China, include Longi solar panel. Jinko solar panel, Canadian Solar panel, ja solar panel etc.all of which are among the top 10 world-renowned brands. The original A grade product is mainly mono crystalline and half cut cell solar modules, with a power range of 400watts to a maximum of 700watts.quality warranty is 25 years.
A grade, this type of film is characterized by a neat and uniform appearance, printed electrode grid lines, no broken grid, no surface stains, no leakage, no aluminum package, no hidden cracks, no scratches, no black core, no reverse current, stable electrical performance, and high conversion efficiency
Using solar cell testing equipment to measure and screen, the conversion efficiency, filling factor, and appearance that meet certain standards are first level. Generally, the conversion efficiency, filling factor, and appearance of first level are better than those of level B
The level of solar panels can be divided into first level, second level, third level, and fourth level, and the first level components can be divided into first level+and first level - two levels. The second level is also the same, and the cost difference between different levels of solar panels is also very large.
Chinese tier 1 brand solar panel
|
TIER 1 brand include
|
Longi, Jinko, Trina, JA, Canadian, znshine, etc.
|
|
quality warranty
|
25 years
|
|
grade
|
original A grade (each solar panel can be checked on official website with barcode)
|
|
power range
|
400watt to max 700watt
|
Tier 1 Solar Panel,Mono Solar Panel N Type,Solar Panels Bifacial 555 Watt,Solar Panel Mono Topcon Cell
PLIER(Suzhou) Photovoltaic Technology Co., Ltd. , https://www.pliersolar.com