DESC:TECHNICAL FIELD
[0001] The present invention relates generally to reconfigurable pulse generators.
BACKGROUND
[0002] Pulses of various shapes such as Step, Gaussian, mono-cycle, and poly-cycle are used for Ultra-wide band communication and radar systems. Mono-cycle is very popular among these because of its wide spectrum and does not contain lower frequency content. Mono-cycle and poly-cycle are generated using the fundamental gaussian pulse. In the open Literature, various ways to generate Gaussian pulse i.e., using varactor diode, MESFET, avalanche Transistor and step recovery diode are disclosed. Gaussian pulse generation using step recovery diode is very popular and efficient. A step recovery diode (SRD) works as a charge controlled switch and its ability to change very rapidly from low impedance to a high impedance state can be used to sharpen the slow waveform edges. Transition time (Tt) and minority carrier lifetime (MCLT) are the most important characteristics of the SRD.
[0003] A Gaussian Pulse generator composed of driver circuit and a pulse sharpener circuit. TTL logic triggers the driver circuit and gives the high voltage output of few nanoseconds which is to be sharpened through pulse sharpener circuit and finally high amplitude Gaussian pulse appeared at the output. The driver circuit can be implemented through bipolar junction Transistor and Field effect Transistor. The sharpener circuit is formed using a parallel combination of Schottky diode (SD) and step recovery diode (SRD) with delay line in between which is responsible for width of the pulse.
[0004] EP 2294693B1 titled “Nanosecond pulse generators” discloses a method of generating high amplitude electric pulses using a resonant circuit and an SRD. This is used for electro perturbation of biological cells through manipulating intracellular structures such as nuclei and mitochondria.
[0005] US 8207885B2 titled “Adjustable pulse width generators” discloses the pulse generation technique using avalanche diode and step recovery diode. This work focuses on more depth of detection, Center frequency is 500 MHz with adjustable band. A control circuitry consists of an avalanche Transistor and a Variable capacitor is used to control the width of the pulse. At least two pulse generators are connected to at least two antennas so that multiple frequencies were sent, and detection was done by differential techniques.
[0006] Therefore, there is a need of an invention which solves the above defined problems and provides a reconfigurable mono-cycle pulse generator. Radar application with higher pulse width gives higher depth of detection but lower resolution and increases the system size and complexity. A pulse generator with higher tunable range of mono-cycle/poly-cycle shape waveforms enhance the performances of the system and reduce the cost.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0007] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.
[0008] FIG. 1 illustrates a schematic diagram depicting a complementary Pulse generator, according to an exemplary implementation of the present invention.
[0009] FIG. 2 illustrates a schematic diagram depicting a complementary driver circuit which provides few nanoseconds pulse width output of positive and negative polarity, according to an exemplary implementation of the present invention.
[0010] FIG. 3 illustrates a schematic diagram depicting Complementary Reconfigurable Gaussian Pulse Generator, according to an exemplary implementation of the present invention.
[0011] FIG. 4 illustrates a schematic diagram depicting a Switched Delay line, according to an exemplary implementation of the present invention.
[0012] FIG. 5 illustrates a schematic diagram depicting a Reconfigurable Pulse Generators Type-I, according to an exemplary implementation of the present invention.
[0013] FIG. 6 illustrates a schematic diagram depictinga Reconfigurable Pulse Generators Type-II, according to an exemplary implementation of the present invention.
[0014] FIG. 7 illustrates a schematic diagram depicting a Poly-cycle Generation Technique, according to an exemplary implementation of the present invention.
[0015] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methodsembodying the principles of the present invention. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
SUMMARY OF THE INVENTION
[0016] This summary is provided to introduce concepts of the present invention. This summary is neither intended to identify essential features of the present invention nor is it intended for use in determining or limiting the scope of the present invention.
[0017] In accordance with the present invention, a mono-cycle gaussian pulse generator is disclosed. The mono-cycle gaussian pulse generator comprises of: one or more driver circuits configured to provide positive and negative pulses, driven by a common trigger pulse; one or more pulse sharpening circuit configured to sharpen the rising and falling edges of the positive and negative pulses; one or more delay lines configured to receiving either of the positive pulse or a negative pulse for generating a delayed pulse and determine the pulse width by determining the delay period; and a power combiner configured to receive the delayed pulse, non-delayed pulse to generate a mono-cycle pulse.
[0018] In one aspect, the driver circuits comprises of: a positive pulse generator comprising a transistor based switching circuit and an amplifier circuit to output a positive pulse; and a negative pulse generator comprising a transistor based switching circuit and an amplifier circuit to output a negative pulse.
[0019] In one aspect, the pulse sharpening circuit comprises of: a dual polarity mounted Step Recovery Diode (SRD) and a Schottky diode configured to sharpen the rising and falling edges of the positive and negative pulses.
[0020] In one aspect, one or more switched delay lines between the Step Recovery Diode (SRD) and Schottky diode control the pulse width of the mono-cycle pulse or the poly-cycle pulse.
[0021] In one aspect, the delay lines comprise of delay line segments and PIN diodes, wherein the PIN diodes are used as switch for selection of segments of a delay line.
[0022] In one aspect, the length of the delay line determines the pulse width of the generated mono-cycle gaussian pulse.
[0023] In In another aspect of the invention, an apparatus to generate mono-cycle gaussian pulse with a variable pulse width is disclosed. The apparatus comprises of: a mono-cycle gaussian generator, a transformer configured to receive the output of a mono-cycle generator to generate a positive and a negative pulse, a switched delay line configured to receive either of the positive or negative pulse to output a delayed pulse, and a wideband power combiner configured to receive the delayed pulse and the non-delayed pulse to output a mono-cycle with a variable pulse width.
[0024] In another aspect of the invention, an apparatus to generate poly-cycle pulse is disclosed. The apparatus comprises: one or more mono-cycle gaussian pulse generators to output one or more mono-cycle gaussian pulses; one or more delay lines configured to receive the gaussian pulses and output one or more pulses with delay; a power combiner configured to combine the pulses with delay and output a poly-cycle pulse.
[0025] In one aspect, the gaussian pulse generators generate pulses of pulse widths T1, T2, T3, …, TN seconds and the one or more delay lines have cumulative delays of T1, T1+T2, T1+T2+T3, …. , T1+T2….+TN.
[0026] In yet another aspect of the invention, a method of generating a gaussian pulse is disclosed. The method comprises of : generating positive and negative pulses, by one or more generating circuits, using a common trigger pulse; sharpening the rising and falling edges of the positive and negative pulses, by a sharpening circuit; generating a delayed pulse and determining the pulse width, of the pulses using a delay line, wherein the delayed pulse is generated using either or positive or negative pulses received from the sharpening circuit; and combining the delayed pulse and the non-delayed pulse to generate a gaussian pulse.
DETAILED DESCRIPTION
[0027] The various embodiments of the present invention describe about a reconfigurable mono-cycle pulse generator. It further provides an improved reconfigurable mono-cycle pulse generator for use in an industrial environment.
[0028] In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
[0029] However, the systems and methods are not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the present invention and are meant to avoid obscuring of the present invention.
[0030] It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0031] In an exemplary embodiment, a single trigger source based complementary Driver Circuit using BJT (Bipolar junction Transistor)/FET (Field effect junction Transistor), provides Complementary polarity high amplitude nano second pulse (of approximately 4nsec to 20nsec).
[0032] In an exemplary embodiment, a reconfigurable complementary pulse sharpener circuit providing variable sharp Gaussian pulses of 200 psec to 600 psec.
[0033] In an exemplary embodiment, are configurable low loss mono-cycle generator without the need ofdifferentiator and using Transformer and switched delay lines having spectralcontent shifted from DC.
[0034] In an exemplary embodiment, are configurable mono-cycle using complementary Gaussian pulse generationwith delayed triggers.
[0035] In an exemplary embodiment, a poly-cycle generator using plurality of gaussian pulse generators.
[0036] In an exemplary embodiment, a reconfigurable mono-cycle pulse generator comprising: a complementary driver circuit, a pulse sharpening circuit, reconfigurable Gaussian pulse generators, differentiator less, a reconfigurable mono-cycle generator, and poly-cycle generator.
[0037] In an exemplary embodiment, the complementary driver circuit provides dual polarity nano second pulses, consists of positive and negative narrow pulse generators driven by a common trigger source. Positive and Negative pulse generators comprise NPN and PNP pairs of BJT.
[0038] In an exemplary embodiment, the pulse sharpening circuit consists of dual polarity mounted SRD and Schottky diode which sharpens the rising and falling edges of the input pulses.
[0039] In an exemplary embodiment, the reconfigurability stems from the switched delay lines between the SRD and Schottky diodes which controls the pulse width of thegaussian pulse.
[0040] In an exemplary embodiment, the mono-cycle generator consists of a transformer and a wideband combiner to combine dual polarity signals.
[0041] In an exemplary embodiment, the reconfigurability of mono-cycle consists of another switched line in accordance with the width of the gaussian pulse providing the variable mono-cycle pulse width.
[0042] In an exemplary embodiment, the poly-cycle generator consists of a plurality of reconfigurable gaussian pulse generators with pulse widths T1, T2, T3, …, TN seconds and a set ofdelay lines with cumulative delays T1, T1+T2, T1+T2+T3, …. , T1+T2….+TN and a wideband power combiner.
[0043] In an exemplary embodiment, the reconfigurable Mono/Poly-cycle Pulse generator for Radar Application is disclosed. The pulse generator consists of complementary driver circuit, complementary sharpener circuit, switched delay line, Transformer circuit, and wideband power combiner. Gaussian pulse, mono/poly cycle of different pulse widths are generated using circuits and sub circuits.
[0044] The present invention provides a reconfigurable high amplitude gaussian/mono-cycle/poly-cycle pulse Generator (100). The pulse generator (100) has three important embodiments, a type of Trigger, a driver circuit (102, 106) and a pulse sharper (104, 108) shown in FIG .1. The driver circuit (102, 106) generates the high amplitude with the pulse width of few nanoseconds which will besharpened by pulse sharpener circuit (104, 108) in the next stage.
[0045] A complementary driver circuit (200) is implemented through BJTs and FETs. First stage is switching, and next stage is amplification. A switching circuit (202, 204) is implemented throughNPN and PNP pair and vice versa depends on the polarity of a desired driver outputpulse shown in FIG.2. Alternately, N-channel FET and P-Channel FET may also beused for switching and next stage amplification, (206, 208). By increasing the order of switching stages (i.e., the pairs of NPN and PNP), narrower pulse is achieved but with a tradeoff between number of switching pair and stability.
[0046] An output of the driver circuit (200) will appear at the input of complementary sharpenercircuit shown in FIG.3, (300). A Shunt Schottky diode (SD) and Step Recovery diode (SRD)connected separated by a delay line (LD) (302) forms the sharpening circuit. Initially, the Schottky diode (SD) is in reverse bias (OFF-state) and step recovery diode is in the forward bias (ON-state). When the driver output pulse appears at the input of pulse sharpening circuit, the falling edge is sharpened, and the pulse appears at the output.Next instant SRD will go to the reverse bias (OFF-state), and it changes the impedance immediately and SD will go to the on state. A portion of a pulse will reflect backtowards SD and will see the short circuit and reflect back to the forward direction with phase shift of 1800. Reflected pulse is sharpened and added to the existing pulse and finally a sharp Gaussian pulse appears at the output. Delay line (302) plays an important role for pulse shaping. Length of the delay line (LD) is chosen in such a way that delay time (td) should be 2LD/Vp, where Vp is the phase velocity of the wave. Delayline (302) is also responsible for pulse width of Gaussian pulse.
[0047] The length of the delay line (302) decides the width of the Gaussian pulse. The switched delay line (400) is the backbone of reconfigurable pulse generators. The switched delay line (400) is designed using delay line segments and PIN diodes as shown in FIG .4. The PIN diode is used asswitch for the selection of segments of delay line. The switched delay line (400) is introduced between the Schottky diode, and the step recovery diode connected in parallel with line.
[0048] The mono-cycle shape of the pulse is very popular because of its wideband spectrum and doesn’t content lower frequencies including DC, so that it can be radiated byantennas. Mono-cycles are generated by differentiating the Gaussian pulse. L-C differentiation is very popular but for reconfigurable pulse generator L-C differentiation will not be applicable.
[0049] In the present invention, to achieve a variable pulse width of mono-cycle, output of the Gaussian pulse generator (Positive /Negative polarity) (502) is connected to the 1:1 transformer. At output two opposite Complementary outputs will appear across the terminals. Any of the output may be delayed using switched delay line (400) and combinedwith the other non-delayed output using wideband power combiner (504). Thus mono-cycle with a variable pulse width can be generated using the circuit shown in Reconfigurable Pulse Generators Type-I (500) FIG. 5.
[0050] Alternately, two independent complementary drivers (602) and pulse sharpening circuits maybe used and combined using the wideband power combiner (504) with a delay at source forone of the drivers. However, the delay should be equal to pulse width of gaussian pulse. This arrangement of the Reconfigurable Pulse Generators Type II (600) is shown in FIG. 6.
[0051] The Poly-cycles are generated through splitting the Gaussian pulse into multiple paths with desired delays and combine them accordingly, by using a tunable gaussian pulse generator (702), a tunable differentiator (704), and a power combiner (706). Delay lines can be used for generation of poly-cycles if all/some of the diodes are in the ON-state. The Poly-cycle is also popular wave form for better detection and enhances the resolution, using accurate delay line designs poly-cycle is achieved as shown in FIG 7, (700).
[0052] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.

,CLAIMS:
1. A mono-cycle gaussian pulse generator, comprising:
one or more driver circuits (102, 106) configured to provide positive and negative pulses, driven by a common trigger pulse;
one or more pulse sharpening circuit (104, 108) configured to sharpen the rising and falling edges of the positive and negative pulses;
one or more delay lines (400) configured to receiving either of the positive pulse or a negative pulse for generating a delayed pulse and determine the pulse width by determining the delay period; and
a power combiner (504) configured to receive the delayed pulse, non-delayed pulse to generate a mono-cycle pulse.

2. The mono-cycle gaussian pulse generator as claimed in claim 1, wherein one or more driver circuits comprises of:
a positive pulse generator comprising a transistor based switching circuit (204) and an amplifier circuit (208) to output a positive pulse; and
a negative pulse generator comprising a transistor based switching circuit (202) and an amplifier circuit (206) to output a negative pulse.

3.The mono-cycle gaussian pulse generator as claimed in claim 1, wherein the pulse sharpening circuit comprise of:
a dual polarity mounted Step Recovery Diode (SRD) and a Schottky diode configured to sharpen the rising and falling edges of the positive and negative pulses.

4. The mono-cycle gaussian pulse generator as claimed in claim 1, wherein one or more switched delay lines between the Step Recovery Diode (SRD) and Schottky diode control the pulse width of the mono-cycle pulse or the poly-cycle pulse.

5. The mono-cycle gaussian pulse generator as claimed in claim 1, wherein the delay lines (400) comprise of delay line segments and PIN diodes, wherein the PIN diodes are used as switch for selection of segments of a delay line.

6. The mono-cycle gaussian pulse generator as claimed in claim 5, wherein the length of the delay line determines the pulse width of the generated mono-cycle gaussian pulse.

7. An apparatus (500) to generate mono-cycle gaussian pulse with a variable pulse width comprising:
a mono-cycle gaussian generator (502) as claimed in any of the claims 1-6;
a transformer configured to receive the output of a mono-cycle generator to generate a positive and a negative pulse;
a switched delay line (400) configured to receive either of the positive or negative pulse to output a delayed pulse;
a wideband power combiner (504) configured to receive the delayed pulse and the non-delayed pulse to output a mono-cycle with a variable pulse width.

8. An apparatus (700) to generate poly-cycle pulse, the apparatus comprising:
one or more mono-cycle gaussian pulse generators (702a-n) as claimed in any of the claims 1-6 to output one or more mono-cycle gaussian pulses;
one or more delay lines (704a-n) configured to receive the gaussian pulses and output one or more pulses with delay;
a power combiner (706) configured to combine the pulses with delay and output a poly-cycle pulse.

9. The apparatus as claimed in claim 8, wherein gaussian pulse generators generate pulses of pulse widths T1, T2, T3, …, TN seconds and the one or more delay lines have cumulative delays of T1, T1+T2, T1+T2+T3, …. , T1+T2….+TN .

10. A method of generating a gaussian pulse, the method comprising:
generating positive and negative pulses, by one or more generating circuits, using a common trigger pulse;
sharpening the rising and falling edges of the positive and negative pulses, by a sharpening circuit;
generating a delayed pulse and determining the pulse width, of the pulses using a delay line, wherein the delayed pulse is generated using either or positive or negative pulses received from the sharpening circuit; and
combining the delayed pulse and the non-delayed pulse to generate a gaussian pulse.