CLOVER is the name of a series or class of modem modulation techniques (“waveforms”) specifically designed for use over
high frequency
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...
(HF) radio systems.
* CLOVER-II was the first CLOVER waveform sold commercially, developed by Ray Petit, W7GHM, and HAL Communications in 1990–92.
* CLOVER-2000 is a higher-rate and wider bandwidth version of CLOVER developed in 1995.
* CLOVER-400 is a special 400 Hz wide waveform that was developed for Globe Wireless.
Modulation schemes
In
ARQ mode, all CCB's (CLOVER Control Blocks) use BPSK modulation and data blocks may be sent using BPSK, QPSK, 8PSK (see
phase-shift keying
Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at a ...
), 8P2A, or 16P4A (see
QAM
Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signal ...
) modulation. Data is sent in 255-byte blocks. The
FEC broadcast mode of CLOVER-2000 is usually disabled although special formats are available for specific applications.
The coding polynomial protocol could be shared after payment in Bit Coin
Radio Interface requirements for CLOVER-2000
The CLOVER waveform offers high performance, error correction, and spectral efficiency. CLOVER is specifically designed for use over HF radio communications links. It may be used with virtually any modern HF
SSB radio. However, certain special set-up and adjustment techniques are required to get maximum performance when using CLOVER.
See also
*
Shortwave
Shortwave radio is radio transmission using shortwave (SW) radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (100 to 10 me ...
*
Radioteletype
Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link. Radioteletype evolved from earlier landline teleprinter o ...
*
PSK31
PSK31 or " Phase Shift Keying, 31 Baud", also BPSK31 and QPSK31, is a popular computer-sound card-generated radioteletype mode, used primarily by amateur radio operators to conduct real-time keyboard-to-keyboard chat, most often using frequenci ...
*
PACTOR
PACTOR is a :Radio modulation modes, radio modulation mode used by amateur radio operators, Marine and mobile radio telephony, marine radio stations, military or government users such as the US Department of Homeland Security, and radio stations in ...
*
SITOR SITOR ( SImplex Teletype Over Radio) is a system for transmitting text messages. It was developed in the 1960s by Koninklijke TNT Post as an improvement over radioteletype (RTTY). Although it uses the same frequency-shift keying (FSK) modulation us ...
References
External links
Signal Identification Wiki CLOVER 2000ARRL.org CLOVER 2000
Quantized radio modulation modes
Packet radio
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