[Photo] Antenna standing wave ratio measurement method

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In an antenna system, whether the antenna is well-connected to the device is usually measured by a parameter called standing wave ratio. When the standing wave ratio is 1, it means that the antenna system is well-matched without reflection. This means that the worse the matching condition, the greater the reflected wave in the system. So how do you measure the VSWR of the antenna? Here I will introduce a simpler method to you.
To measure the standing wave ratio, a frequency sweeper is needed. The connection method is shown in Figure 2-1. First, short-circuit the terminal of the feeder (near the antenna system). At this time, the signal output by the frequency sweeper forms a total reflection at the terminal of the feeder. Observe the total reflection waveform as shown in Figure 2-2. The maximum amplitude of the curve is a, and then connect the antenna to the terminal of the feeder. At this time, the maximum amplitude observed on the frequency scanner within the operating frequency range is b. As shown in Figure 2-3, First find the reflection coefficient P = b / a, then use the formula S = 1 + P / 1-P to find the standing wave ratio, where S represents the standing wave ratio.

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Asic Miner

Application-Specific Integrated Circuit refers to an integrated circuit specifically designed to perform a specific computing task. It is very common to use ASIC for mining in the field of blockchain. This article will analyze the principle of ASIC mining and why it should be anti-ASIC.


For Bitcoin, mining has gone through four stages: CPU, GPU, FPGA and ASIC. GPU is naturally suitable for parallel simple operations, so the execution of SHA256 is much higher than the CPU. FPGA is a programmable hardware, because it has a certain degree of universality, so the unit price will be relatively expensive. ASIC has a large initial design investment, but the unit price will be cheaper after mass production. Therefore, if you can determine that the market size is relatively large, the use of ASIC technology will be the most cost-effective.

This is the basic principle of ASIC.


In a nutshell, mining is running complicated calculations in the search for a specific number. Whether it`s an ASIC miner or a GPU mining rig, mining hardware must run through many calculations before finding that number. In proof of work systems like Bitcoin, the first one to find that number gets a reward - at the time of writing, 12.5 Bitcoins worth around $96,850. That reward will fall to 6.25 Bitcoins in May 2020.

There are so many people and powerful computing systems trying to mine Bitcoin that miner groups form to find that number and share the profit. Even more, the faster your hardware, the more you earn. That`s why people who can afford it opt for ASIC miners because it gives them the greatest chance of earning cryptocurrency in exchange for their investment.

Each cryptocurrency has its own cryptographic hash algorithm, and ASIC miners are designed to mine using that specific algorithm. Bitcoin ASIC miners are actually designed to calculate the SHA-256 hash algorithm. In the case of Litecoin, it uses Scrypt. That means technically they could mine any other coin that`s based on the same algorithm, though typically, people who buy ASIC hardware designed for Bitcoin mine that specific digital currency.

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