Hybrid spread spectrum communication system Using this hybrid method can greatly improve the performance of the spread spectrum system, and it has good communication concealment, strong anti-interference ability, and the carrier frequency of the frequency hopping system is difficult to capture, which is easy to adapt to multiple access communication or discrete addressing and multiplexing. Features such as use, especially when the spreading code rate is too high or the number of frequency hops is too large, the use of this hybrid system is particularly advantageous. From the above introduction, we can see that in addition to the linear pulse frequency modulation method that is rarely used in communication, the remaining several spreading methods can be arbitrarily combined to form a hybrid spread spectrum communication system. From a theoretical point of view, this is no doubt, but there are still some problems that need to be solved in engineering implementation, such as in frequency hopping-direct sequence hybrid spread spectrum systems, due to the synchronization of the spreading codes in the direct sequence system The acquisition time cannot be too short, which limits the frequency hopping rate of the frequency hopping system, and it is difficult to ensure the continuity of the hopping carrier phase in the frequency hopping system, which further increases the spreading code sequence of the direct sequence system Synchronous capture time. Another example is the high-frequency switch problem of a hybrid spread-spectrum system composed of a time-hopping system. In Figure 1-9, we have not drawn the power amplifier of the transmitter. If the high-frequency switch is placed behind the power amplifier, does it exist? The high-frequency switch with short switching time and high load can be developed. At present, the domestic high-frequency switch level is on the order of ns at low power, and the switching time of tens to hundreds of mW is tens of ns. When the power is in the range of tens to hundreds of W, the switching time is on the order of? S ~ ms; if the high frequency switch is placed in front of the power amplifier, the transmitter's emission settling time will be longer, because the power of the output signal of the power amplifier It takes time from scratch, and the establishment of energy cannot be completed in an instant.
Innosilicon Machine:Innosilicon A10 ETHMaster (500Mh),Innosilicon A10 Pro ETH (500Mh),Innosilicon A10 Pro+ ETH (750Mh),Innosilicon A11 Pro ETH (1500Mh)
Innosilicon is a worldwide one-stop provider of high-speed mixed signal IPs and ASIC customization with leading market shares in Asian-Pacific market for 10 consecutive years. Its IP has enabled billions of SoC's to enter mass production, covering nodes from 180nm to 5nm across the world`s foundries including: GlobalFoundries, TSMC, Samsung, SMIC, UMC and others. Backed by its 14 years of technical expertise in developing cutting-edge IPs and ASIC products, Innosilicon has assisted our valued partners including AMD, Microchip and Microsoft to name but a few, in realizing their product goals.
Innosilicon Machine,A11 Pro 1500M Miner,Asic Miner A11 Pro 8G,A11 Pro 8G 1500Mh,ETC miner Shenzhen YLHM Technology Co., Ltd. , https://www.ylhm-tech.com
The above basic spread spectrum communication systems have their own advantages and disadvantages. Sometimes it is difficult to meet the requirements when using one of the systems alone. The combination of the above several spreading methods constitutes a hybrid spread spectrum communication system. Common frequency hopping-direct sequence hybrid systems (FH / DS), direct sequence-time hopping hybrid systems (DS / TH), frequency hopping-time hopping hybrid systems (HF / TH), etc. They have better performance than a single direct sequence, frequency hopping, and time hopping system.
(1) Frequency hopping-direct sequence hybrid system Frequency hopping-direct sequence hybrid system can be regarded as a direct sequence spread spectrum system with carrier frequency as periodic hopping. Its system composition block diagram is shown in Figure 1-11. 
Figure 1-11 Block diagram of frequency hopping-direct sequence hybrid spread spectrum system
(a) transmitting system; (b) receiving system
(2) Time-hopping-frequency hopping hybrid system Time-hopping-frequency hopping hybrid system is especially suitable for a large number of stations working at the same time, whose distance or transmission power varies within a large range, and needs to solve the problem of near-far effect in communication .
Far-near effect means that in the same working area, in the same system, because the receiver has different distances to different transmitters, the propagation distance of the radio waves is different, and the attenuation of the radio wave propagation path is different. The field strength of the signal sent by the remote transmitter. In the receiver, the strong signal will suppress the weak signal, causing the receiver to not receive the signal from the remote transmitter well.
This system hopes to use simple coding as the address code, mainly for multiple access and addressing, and spread spectrum is not the main purpose.
(3) Time-hopping-direct sequence hybrid system When the number of different spreading code sequences used in the direct sequence system cannot meet the multiple access or multiplexing requirements, increasing time division multiplexing (TDM) is an effective solution. This can not only increase the number of addresses, but also improve the interference of adjacent stations, forming a so-called time hopping-direct sequence hybrid spread spectrum system. The block diagram of time hopping-direct sequence hybrid spread spectrum system is shown in Figure 1-12. 
Figure 1-12 Time hopping-direct sequence hybrid spread spectrum system block diagram
(a) transmitting system; (b) receiving system
Therefore, when designing a specific system, it is necessary to conduct specific analysis based on specific problems, and more issues to be considered are whether it can be achieved in engineering. Blindly pursuing high indicators regardless of the degree of difficulty in engineering implementation is likely to make the designed system not The most reasonable or optimal.
Innosilicon team is fully devoted to providing the world's most advanced IP and ASIC technologies, and has achieved stellar results. In 2018, Innosilicon was the first in the world to reach mass production of the performance-leading GDDR6 interface in our cryptographic GPU product. In 2019, Innosilicon announced the availability of the HDMI v2.1 IP supporting 4K/8K displays as well as our 32Gbps SerDes PHY. In 2020, we launched the INNOLINK Chiplet which allows massive amounts of low-latency data to pass seamlessly between smaller chips as if they were all on the same bus. With a wide range of performance leading IP in multiple FinFET processes and 22nm planar processes all entering mass production, Innosilicon's remarkable innovation capabilities have been proven in fields such as: high-performance computing, high-bandwidth memory, encrypted computing, AI cloud computing, and low-power IoT.