- 1 What is linear frequency modulation?
- 2 What is LFM signal?
- 3 What is transmit pulse?
- 4 How do you perform a pulse compression?
- 5 What is linear frequency?
- 6 Why is chirp used in radar?
- 7 What is LFM pulse?
- 8 What is cross ambiguity function?
- 9 What is frequency modulation?
- 10 Why do we use pulse shaping?
- 11 Is pulse signal analog or digital?
- 12 Is a rectangular pulse a Nyquist pulse?
- 13 Who invented pulse compression?
- 14 How is pulse compression gain calculated?
- 15 What is pulse compression ratio?
What is linear frequency modulation?
The linear frequency modulation is used to resolve two small targets that are located at long range with very small separation between them. The primary focus of this paper is the time frequency analysis and generation of LFM waveform using Direct Digital Chirp Synthesis (DDCS).
What is LFM signal?
The linear frequency modulation (LFM) signal is a typical LPI radar signal, and it has been widely used in synthetic aperture radar (SAR). LFM signal has the advantages of good concealment, wide bandwidth, low peak power, and strong anti-interference.
What is transmit pulse?
In pulse transmission systems, pulses modulated in various ways to carry information may be transmitted by amplitude, phase or frequency modulation of a carrier, and with each type of modulation various methods of detection are possible.
How do you perform a pulse compression?
Pulse compression is a signal processing technique commonly used by radar, sonar and echography to increase the range resolution as well as the signal to noise ratio. This is achieved by modulating the transmitted pulse and then correlating the received signal with the transmitted pulse.
What is linear frequency?
Regular or linear frequency (f), sometimes also denoted by the Greek symbol “nu” (ν), counts the number of complete oscillations or rotations in a given period of time. Its units are therefore cycles per second (cps), also called hertz (Hz). Hence, 1 Hz ≈ 6.28 rad/sec.
Why is chirp used in radar?
The chirp pulse compression process transforms a long duration frequency-coded pulse into a narrow pulse of greatly increased amplitude. It is a technique used in radar and sonar systems because it is a method whereby a narrow pulse with high peak power can be derived from a long duration pulse with low peak power.
What is LFM pulse?
Abstract: Radar system uses Pulse compression techniques to provide the benefits of larger range detection and high range resolution. In the past several pulse compression techniques are used, out of which the well known method is linear frequency modulation (LFM).
What is cross ambiguity function?
The cross-ambiguity function is a time ( ) and frequency ( ) analysis technique employed to solve many signal processing problems such as interference mitigation and the location of emitters.
What is frequency modulation?
Frequency Modulation (FM) is the encoding of information in a carrier wave by changing the instantaneous frequency of the wave. FM technology is widely used in the fields of computing, telecommunications, and signal processing.
Why do we use pulse shaping?
In electronics and telecommunications, pulse shaping is the process of changing the waveform of transmitted pulses. Its purpose is to make the transmitted signal better suited to its purpose or the communication channel, typically by limiting the effective bandwidth of the transmission.
Is pulse signal analog or digital?
PULSE TRAIN SIGNAL CONDITIONING A pulse can be considered a digital signal because only the number of rising or falling edges is measured. In many instances, however, the pulse-train signal comes from an analog source, such as a magnetic pickup.
Is a rectangular pulse a Nyquist pulse?
Thus, the sequence of sinc pulses resulting from a locked phase, rectangular frequency comb satisfies the Nyquist criterion for free ISI within every pulse repetition period T.
Who invented pulse compression?
Pulse compression (aka ‘chirp’) radar was invented in the 1950s by Sperry and a couple other defense contractors.
How is pulse compression gain calculated?
The pulse compression ratio can be expressed as the ratio of the range resolution of an unmodulated pulse of length τ to that of the modulated pulse of the same length and bandwidth B. The compression ratio is equal to the number of sub pulses in the waveform, i.e., the number of elements in the code.
What is pulse compression ratio?
The ratio of the transmitted pulse width to the compressed (or processed) pulse width is called the pulse compression ratio. There are two primary classes of pulse compression: analog and digital. For analog compression, the transmitted waveform is a linear FM pulse.