Does anyone play this "RTL-SDR receiver"

I. Concept

Software radio is a radio communication system. It is usually implemented by hardware components (such as mixers, filters, amplifiers, modulators and demodulators, detectors, etc.). ) is now implemented by software on personal computers or embedded systems. Although software-defined radio (SDR) is not a new concept, it involves many fast digital electronic development capabilities, which were only theoretically possible in the past.

A basic SDR system may consist of a personal computer with a sound card or other analog-to-digital converter and some form of RF front-end. A large number of signals are processed by a general-purpose processor instead of using special hardware. The radio generated by this design can receive and transmit various radio protocols (sometimes called waveforms) completely based on the software used.

Second, the composition principle

These DVB-T receivers are based on Realtek's RTL2832U chip and a tuner, such as Elonics E4000. RTL2832U chip has some useless commands/registers. Based on these commands/registers, the unprocessed original baseband sampling signal (up to 2.8 MS/s 8-bit I+Q) can be configured to be transmitted to PC through high-speed USB.

1, Software Radio (SDR) is a radio communication system. It is usually implemented by hardware components (such as mixers, filters, amplifiers, modulators and demodulators, detectors, etc.). ) is now implemented by software on personal computers or embedded systems. Although software-defined radio (SDR) is not a new concept, it involves many fast digital electronic development capabilities, which were only theoretically possible in the past.

2. The basic SDR system can be composed of personal computers with sound cards or other analog-to-digital converters and some form of RF front-end. A large number of signals are processed by a general-purpose processor instead of using special hardware. The radio generated by this design can receive and transmit various radio protocols (sometimes called waveforms) completely based on the software used.

3. Working principle In SDR mode, the antenna directly enters the silicon tuner (E4000 or R820T), and the silicon tuner has a built-in PLL and mixer (E4000 is zero IF mode and R820T is low IF mode). The mixer is amplified by PGA and input to the ADC of RTL2832U (E4000 is the I/Q channel and R820T is only the I channel), and the ADC collects it. ExtIO is the device abstract interface of HDSDR, which is used to control SDR receiver and receive data.

Third, the role and use

It can be described as an all-band radio receiver (100KHz- 1.7GHz), which can be connected to computers, Android phones and other devices, and uses SDR software to receive electromagnetic waves of 100KHz- 1.7GHz, and supports AM, FM(NFM, WFM) and FM. Can listen to medium wave, short wave, FM broadcast, short wave single sideband communication, walkie-talkie communication, aviation band and so on. The R820T2 tuner has slightly higher sensitivity, lower background noise and higher signal-to-noise ratio than the R820T2 tuner.

For wireless enthusiasts, SDR receiver is an illustrated radio receiver with hardware and software, which can even be regarded as the simplest spectrum analyzer, so SDR is very suitable for radio enthusiasts to learn.

The device has two antenna interfaces. The first one needs to be received by a short-wave antenna from 0. 1MHz to 30MHz (more troublesome), and the second one needs to be received by a rod antenna from 30MHz to 1.7GHz.

If you are an amateur radio lover, you can use software to visually see radio activities within a certain frequency range on your computer.

For example, similar to a simple spectrum analyzer, find out whether the intercom frequency of a certain frequency is relayed, find out the best frequency (frequency point) of the signal, check the occupation of all frequencies in the frequency range from 400MHz to 470MHz, and at the same time, see which frequency has the highest signal strength in this frequency range; You can also find a relay station. Generally, signals are generated in similar frequency band 437.800, and signals are also generated in 435.800, and two different frequencies work at the same time.