Accession Number:

ADD010160

Title:

Frequency-Phase Coding Device.

Descriptive Note:

Patent,

Corporate Author:

DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s):

• Lewis,Bernard L.

Report Date:

1982-11-16

Pagination or Media Count:

7.0

Abstract:

This invention relates to a doppler-tolerant pulse-compression code generator for generating a plurality of approximately orthogonal codes which will prevent radar interference and suppress jamming. These codes are generated by phase-coding the frequency-band steps and also altering the time-sequence of the frequency steps of a step-approximation to a linear FM chirp pulse. Specifically, this code generator may comprise a circuit for modulating a carrier frequency with a video pulse of bandwidth B having a length less than or equal to a desired compressed pulse length, a tapped delay line having n signal taps for sequentially delaying this video pulse, a comb filter comprising a series of n bandpass filter channels each passing different spectral bands in the bandwidth B, a switching matrix for connecting each of the n signal taps to a different one of the n bandpass filters in a controlled manner, a phase-coding circuit in each bandpass filter channel for phase coding the signal passed through the respective bandpass filter channel, and an adding circuit for adding all of the phase-coded signals from the n bandpass filter channels to form one of a set of orthogonally coded pulses. Author

Descriptors:

• *Patents
• *Radar interference
• *Chirp radar
• *Antijamming
• *Radiofrequency interference
• *Coders
• Jamming
• Frequency modulation
• Orthogonality
• Pulse compression
• Phase
• Carrier frequencies
• Bandpass filters
• Pulses
• Delay lines
• Bandwidth
• Switching
• Signals
• Filters
• Taps
• Length
• Channels
• Video signals

Subject Categories:

• Radio Countermeasures
• Active and Passive Radar Detection and Equipment
• Radiofrequency Wave Propagation
• Non-Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE