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Method and apparatus for activating and implementing adaptive countermeasures for wireless communication of Fast Ethernet data packets. A terminal for a wireless communication link includes a data packet receiver for receiving data packets, a packet formatting apparatus coupled to the data packet re

Method and apparatus for activating and implementing adaptive countermeasures for wireless communication of Fast Ethernet data packets. A terminal for a wireless communication link includes a data packet receiver for receiving data packets, a packet formatting apparatus coupled to the data packet receiver for formatting the data packets according to radio frames, a wireless transceiver coupled to the packet formatting apparatus for communicating the radio frames over a wireless link, and a processor coupled to the packet formatting apparatus for selectively activating a technique for altering a manner in which the radio frames are communicated over the wireless link. The method can include a step of selectively activating a technique for implementing flow control on the data packets. The broadcast device can monitor a bit error rate associated with radio frames communicated and, in response to the bit error rate, can activate the technique for altering the manner in which the radio frames are communicated. The broadcast device can also monitor a received signal level associated with radio frames communicated and, in response to the received signal level, can activate the technique for altering the manner in which the radio frames are communicated. The technique can alter error correction coding, spectrum spreading, power level, data transmission rate, or modulation scheme utilized for transmitting the radio frames. The packet formatting apparatus includes an adaptive countermeasures apparatus having a plurality of selectively active paths, each path implementing a selected technique for altering the manner in which the radio frames are communicated.

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Method and apparatus for activating and implementing adaptive countermeasures for wireless communication of Fast Ethernet data packets. A terminal for a wireless communication link includes a data packet receiver for receiving data packets, a packet formatting apparatus coupled to the data packet re

Method and apparatus for activating and implementing adaptive countermeasures for wireless communication of Fast Ethernet data packets. A terminal for a wireless communication link includes a data packet receiver for receiving data packets, a packet formatting apparatus coupled to the data packet receiver for formatting the data packets according to radio frames, a wireless transceiver coupled to the packet formatting apparatus for communicating the radio frames over a wireless link, and a processor coupled to the packet formatting apparatus for selectively activating a technique for altering a manner in which the radio frames are communicated over the wireless link. The method can include a step of selectively activating a technique for implementing flow control on the data packets. The broadcast device can monitor a bit error rate associated with radio frames communicated and, in response to the bit error rate, can activate the technique for altering the manner in which the radio frames are communicated. The broadcast device can also monitor a received signal level associated with radio frames communicated and, in response to the received signal level, can activate the technique for altering the manner in which the radio frames are communicated. The technique can alter error correction coding, spectrum spreading, power level, data transmission rate, or modulation scheme utilized for transmitting the radio frames. The packet formatting apparatus includes an adaptive countermeasures apparatus having a plurality of selectively active paths, each path implementing a selected technique for altering the manner in which the radio frames are communicated. p 2c consisting of a second cemented lens component, and satisfies the following condition (1): 0.042N/t22Nis an optical axis distance from an image-side surface of the positive lens 2a located on the object side of the second lens group to an image-side surface of the negative lens 2b in the second lens group, and t2is an optical axis distance from an object-side surface of the positive lens 2a located on the object side of the second lens group to a surface located to an image side of the second lens group 2c. 2. An electronic image pickup system comprising a zoom lens system and an electronic image pickup device located in the rear of said zoom lens system, wherein: said zoom lens system comprises, in order from an object side of said zoom lens system, a first lens group having negative refracting power, a second lens group having positive refracting power and a third lens group having positive refracting power, upon focused on an object point at infinity, a separation between said second lens group and said third lens group becomes wide for zooming from a wide-angle end to a telephoto end of said zoom lens system, said zoom lens system is focused on a nearby subject by moving said the third lens group toward the object side, and said second lens group comprises, in order from an object side thereof, a first cemented lens component comprising a positive lens 2a and a negative lens 2b and a second lens group 2c consisting of a second cemented lens component, and satisfies the following condition (2): -0.52a/f2c2a,and f2cis a focal length in air of the positive lens 2a located on the object side of the second lens group, and the lens group 2c, respectively. 3. An electronic image pickup system comprising a zoom lens system and an electronic image pickup device located in the rear of said zoom lens system, wherein: said zoom lens system comprises, in order from an object side of said zoom lens system, a first lens group having negative refracting power, a second lens group having positive refracting power and a third lens group having positive refracting power, upon focused on an object point at infinity, a separation between said second lens group and said third lens group becomes wide for zooming from a wide-angle end to a telephoto end of said zoom lens system, said zoom lens system is focused on a nearby subject by moving said the third lens group toward the object side, said second lens group comprises a first cemented lens and a second cemented lens, and said zoom lens system has a zoom ratio of 2.3 or greater. 4. An electronic image pickup system comprising a zoom lens system and an electronic image pickup device located in the rear of said zoom lens system, wherein: said zoom lens system comprises, in order from an object side of said zoom lens system, a first lens group having negative refracting power, a second lens group having positive refracting power and a third lens group having positive refracting power, upon focused on an object point at infinity, a separation between said second lens group and said third lens group becomes wide for zooming from a wide-angle end to a telephoto end of said zoom lens system, said zoom lens system is focused on a nearby subject by moving said the third lens group toward the object side, and said second lens group consists of, in order from an object side thereof, a cemented lens component comprising a positive lens 2a and a negative lens 2b and a lens group 2c consisting of a single lens component, and satisfies the following condition (1): 0.042N/t22Nis an optical axis distance from an image-side surface of the positive lens 2a located on the object side of the second lens group to an image-side surface of the negative lens 2b in the second lens group, and t2is an optical axis distance from an object-side surface of the positive lens 2a located on the object side of the second lens group to a surface located to an image side of the second lens group 2c. 5. An electronic image pickup system comprising a zoom lens system and an electronic image pickup device located in the rear of said zoom lens system, wherein: said zoom lens system comprises, in order from an object side of said zoom lens system, a first lens group having negative refracting power, a second lens group having positive refracting power and a third lens group having positive refracting power, upon focused on an object point at infinity, a separation between said second lens group and said third lens group becomes wide for zooming from a wide-angle end to a telephoto end of said zoom lens system, said zoom lens system is focused on a nearby subject by moving said the third lens group toward the object side, and said second lens group consists of, in order from an object side thereof, a cemented lens component comprising a positive lens 2a and a negative lens 2b and a lens group 2c consisting of a single lens component, and satisfies the following condition (2): -0.52a/f2c2a,and f2cis a focal length in air of the positive lens 2a located on the object side of the second lens group, and the lens group 2c, respectively. 6. An electronic image pickup system comprising a zoom lens system and an electronic image pickup device located in the rear of said zoom lens system, wherein: said zoom lens system comprises, in order from an object side of said zoom lens system, a first lens group having negative refracting power, a second lens group having positive refracting power and a third lens group having positive refracting power, upon focused on an object point at infinity, a separation between said second lens group and said third lens group becomes wide for zooming from a wide-angle end to a telephoto end of said zoom lens system, said zoom lens system is focused on a nearby subject by moving said the third lens group toward the object side, said second lens group consists of one cemented lens and one single lens component, and said zoom lens system has a zoom ratio of 2.3 or greater. 7. The electronic image pickup system according to claims 1, 2 or 3, wherein said second lens group consists of two cemented lenses; said first cemented lens and said second cemented lens. 8. The electronic image pickup system according to any one of claims 1 to 6, wherein, in said zoom lens system, lens groups having optical power are only said first lens group, said second lens group and said third lens group. 9. The electronic image pickup system according to any one of claims 1 to 6, wherein said third lens group consists of one lens component. 10. The electronic image pickup system according to any one of claims 1 to 6, wherein a plurality of plane-parallel plates including a low-pass filter are interposed between said third lens group and a color mosaic filter in said electronic image pickup device. 11. The electronic image pickup system according to claim 1 or 4, which comprises a zoom lens wherein said lens group 2c in said second lens group comprises an aspherical surface, and said third lens group consists of only of a spherical surface or comprising an aspherical surface that satisfies the following condition (3): abs(z)/L-2 (3) where abs(z) is an absolute value of an amount of a deviation of the aspherical surface in the third lens group from a spherical surface having an axial radius of curvature in an optical axis as measured at a height of 0.35 L from the optical axis, and L is a diagonal length of an effective image pickup plane. 12. The electronic image pickup system according to claim 1 or 4, which comprises a zoom lens that satisfies the following conditions (4) and (5): (R2c1+R2cr)/(R2c1 -R2cr)31+R32)/(R31-R32)2c1and R2crare axial radii of curvature of the surfaces in the image-side lens group 2c in the second lens group, which surfaces are located nearest to the object and image sides, respectively, and R31and R32are axial radii of curvature of the first and second lens surfaces in the third lens group, respectively, as counted from the object side. 13. The electronic image pickup system according to claim 1 or 4, which comprises a zoom lens that satisfies the following condition (6): -1.52a1+R2a2)·(R2b1-R2b2)}/I(R2a1-R2a2)·(R2b1+R2b2)}2a1and R2a2are axial radii of curvature on the object and image sides, respectively, of the lens 2a in the second lens group, and R2b1and R2b2are axial radii of curvature on the object and image sides, respectively, of the lens 2b in the second lens group. 14. The electronic image pickup system according to claim 1 or 4, which comprises a zoom lens wherein the lens 2a in said second lens group has an aspherical surface on an object-side surface thereof. 15. The electronic image pickup system according to claim 1 or 4, which comprises a zoom lens wherein said first lens group comprises, in order from an object side thereof, a negative lens group comprising up to 2 negative lenses and a positive lens group comprising one positive lens, at least one negative lens in said lens group comprises an aspherical surface, and the following condition (7) is satisfied: -0.1W/R1111is an axial radius of curvature of the first lens surface in the first lens group, as counted from the object side, and fW is a focal length of the zoom lens system at a wide-angle end thereof upon focused on an object point at infinity. 16. The electronic image pickup system according to claim 1 or 4, which comprises a zoom lens that satisfies the following condition (8): 0.13Np/fWNpis an axial air separation between the negative and positive lens groups in the first lens group. 17. The electronic image pickup system according to claim 4, which comprises a zoom lens wherein said first lens group consists of, in order from an object side thereof, one positive lens, two negative lenses and one positive lens. 18. The electronic image pickup system according to claim 17, which comprises a zoom lens that satisfies the following condition (9): 0.7514/L14is an axial radius of curvature of the fourth lens surface in the first lens group, as counted from the object side, and L is a diagonal length of an effective image pickup area of the image pickup device. 19. The electronic image pickup system according to claim 1 or 4, wherein said first lens group, and said second lens group has a total thickness that satisfies the following conditions (11) and (12): 0.41/L2/L1is an axial thickness of the first lens group from a lens surface located nearest to an object side thereof to an lens surface located nearest to an image side thereof, t2is an axial thickness of the second lens group from a lens surface located nearest to an object side thereof to a lens surface located nearest to an image side thereof, and L is a diagonal length of an effective image pickup area of the image pickup device. 20. The electronic image pickup system according to claim 1 or 4, wherein an optical low-pass filter located between said image pickup device and the object side of said electronic image pickup system has a total thickness that satisfies the following condition (13): 0.15×103LPF/a3 (13) where tLPFis the total thickness of said optical low-pass filter and a is a horizontal pixel pitch of said image pickup device.