28-05-2012, 11:01 AM
APPLICATION OF PSK MODULATION FOR VERY SLOW DATA TRANSMISION
[attachment=23262]
ABSTRACT
In this paper, a frequency band saving PSK based modulation for very slow data transmission is described. There is often needed to transmit very slow character sequences as satellite telemetry data by a very narrow channel. The article shows the method of a digital modulation and demodulation and advantages of PSK31 operation uses DPSK or QPSK with convolutional coding. PSK31 has been developed by Peter Martinez for keyboard to keyboard communication and there is tested for high Doppler shift satellite applications.
PSK MODULATION
Phase shift keying (PSK) is a one of most frequently efficient modulation technique for wireless data transmision for its high noise immunity and narrow frequency bandwidth. Binary phase shift keying (BPSK) is the simplest type of phase keying. Signal elements of BPSK are represented by following relations
PSK IN VERY SLOW DATA TRANSMISION
There are simple low-cost hardware narrow band systems used to transmission of short messages with low information capacity. The typical system has been radioteletype (RTTY) with a not very effective AFSK (Audio Frequency Shift Keying) modulation. Later, this system was modified for a BPSK modulation (Pawel Jalocha, SLOWPSK). The new perspective system developed particularly for keyboard to keyboard communication is PSK31 [1]. With regard to this exploitation there was baud rate specified for 5 characters per sec typing. The optimal baud rate is 31.25 Bd at the 8 kHz sampling frequency and Varicode coding. PSK31 uses DPSK or QPSK at the same baud rate but in case of QPSK with convolutional coding. This operation is good for else purposes than keyboard to keyboard communication for its narrow bandwidth, noise immunity and simple hardware realization. For example, a low orbital satellite (LEO) telemetric data transmission could use PSK31 because there is a high Doppler effect expanded the frequency spectrum.
CONCLUSION
PSK31 is an easy implemented and hardware unassuming system for very slow data transmisions. Narrow asked bandwidth and noise immunity makes possible to use PSK31 in overcrowded short-wave bands. Currently a satellite receiver for the 29.4 MHz and an experimental transponder for Doppler shift simulation are being developed. The improvement of PSK31 for telemetric data transmission from LEO satellites is going to test.
[attachment=23262]
ABSTRACT
In this paper, a frequency band saving PSK based modulation for very slow data transmission is described. There is often needed to transmit very slow character sequences as satellite telemetry data by a very narrow channel. The article shows the method of a digital modulation and demodulation and advantages of PSK31 operation uses DPSK or QPSK with convolutional coding. PSK31 has been developed by Peter Martinez for keyboard to keyboard communication and there is tested for high Doppler shift satellite applications.
PSK MODULATION
Phase shift keying (PSK) is a one of most frequently efficient modulation technique for wireless data transmision for its high noise immunity and narrow frequency bandwidth. Binary phase shift keying (BPSK) is the simplest type of phase keying. Signal elements of BPSK are represented by following relations
PSK IN VERY SLOW DATA TRANSMISION
There are simple low-cost hardware narrow band systems used to transmission of short messages with low information capacity. The typical system has been radioteletype (RTTY) with a not very effective AFSK (Audio Frequency Shift Keying) modulation. Later, this system was modified for a BPSK modulation (Pawel Jalocha, SLOWPSK). The new perspective system developed particularly for keyboard to keyboard communication is PSK31 [1]. With regard to this exploitation there was baud rate specified for 5 characters per sec typing. The optimal baud rate is 31.25 Bd at the 8 kHz sampling frequency and Varicode coding. PSK31 uses DPSK or QPSK at the same baud rate but in case of QPSK with convolutional coding. This operation is good for else purposes than keyboard to keyboard communication for its narrow bandwidth, noise immunity and simple hardware realization. For example, a low orbital satellite (LEO) telemetric data transmission could use PSK31 because there is a high Doppler effect expanded the frequency spectrum.
CONCLUSION
PSK31 is an easy implemented and hardware unassuming system for very slow data transmisions. Narrow asked bandwidth and noise immunity makes possible to use PSK31 in overcrowded short-wave bands. Currently a satellite receiver for the 29.4 MHz and an experimental transponder for Doppler shift simulation are being developed. The improvement of PSK31 for telemetric data transmission from LEO satellites is going to test.