Multi-channel digital transmitter and receiver

Claim 2

A filter comprising a plurality of conditioning means for conditioning a digitized signal during digital signal processing, each conditioning means comprising an integrator, at least one differencer, and at least one multiplier operatively coupled together to condition a portion of the digitized signal.

Claim 3

The filter of claim 1 wherein: (a) the at least one differencer of each conditioning means comprises a first and a second differencer, each operatively coupled to an output of the integrator, the second differencer being operatively coupled through a delay element; (b) the at least one multiplier of each conditioning means comprises a first and a second multiplier, operatively coupled to the first and the second differencer, respectively, for generating scaled outputs of the first and the second differencer; and (c) each conditioning means further comprises a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 4

The filter of claim 2 wherein: (a) each conditioning means further comprises: (i) a third differencer operatively coupled to an output of the integrator through at least two delay elements; and (ii) a third multiplier, operatively coupled to the third differencer, for generating a scaled output of the third differencer; and (b) the summing means is further operatively coupled to the third multiplier, for generating the portion of the conditioned digitized signal from the scaled output of the third multiplier.

Claim 5

The filter of claim 1 wherein: (a) the integrator of each conditioning means is operatively coupled to an output of the differencer of each conditioning means; (b) the at least one multiplier of each conditioning means comprises a first and a second multiplier, operatively coupled to the integrator, for generating scaled outputs of the integrator, the second multiplier being operatively coupled through a delay element; and (c) each conditioning means further comprises a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 6

The filter of claim 4 wherein: (a) each conditioning means further comprises a third multiplier, operatively coupled to an output of the integrator through at least two delay elements, for generating a scaled output of the integrator; and (b) the summing means is further operatively coupled to the third multiplier, for generating the portion of the conditioned digitized signal from the scaled output of the third multiplier.

Claim 7

A filter comprising a plurality of pre-conditioning means for pre-conditioning a digitized signal for subsequent digital signal processing, each pre-conditioning means comprising: (a) an integrator; (b) a first and a second differencer, each operatively coupled to an output of the integrator, the second differencer being operatively coupled through a delay element; (c) a first and a second multiplier, operatively coupled to the first and the second differencer, respectively, for generating a scaled output of the first and the second differencer; and (d) a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 8

A filter comprising a plurality of pre-conditioning means for pre-conditioning a digitized signal for subsequent digital signal processing, each pre-conditioning means comprising: (a) an integrator; (b) a first and a second differencer, each operatively coupled to an output of the integrator, the second differencer being operatively coupled through a delay element; (c) a first and a second multiplier, operatively coupled to the first and the second differencer, respectively, for generating a scaled output of the first and the second differencer; and (d) a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 9

The filter of claim 6 further comprising a first and a second decimating means, operatively coupled to the first and the second differencer, respectively, for reducing a sample rate of the integrator input to the first and the second differencer.

Claim 10

The filter of claim 6 wherein: (a) each pre-conditioning means further comprises: (i) a third differencer operatively coupled to an output of the integrator through at least two delay elements; and (ii) a third multiplier, operatively coupled to the third differencer, for generating a scaled output of the third differencer; and (b) the summing means is further operatively coupled to the third multiplier, for generating the portion of the pre-conditioned digitized signal from the scaled output of the third multiplier.

Claim 11

A filter comprising a plurality of post-conditioning means for post-conditioning a digitized signal after digital signal processing, each post-conditioning means comprising: (a) a differencer; (b) an integrator operatively coupled to an output of the differencer; (c) a first and a second multiplier, operatively coupled to the integrator, for generating a scaled output of the integrator, the second multiplier being operatively coupled through a delay element; and (d) a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 12

A filter comprising a plurality of post-conditioning means for post-conditioning a digitized signal after digital signal processing, each post-conditioning means comprising: (a) a differencer; (b) an integrator operatively coupled to an output of the differencer; (c) a first and a second multiplier, operatively coupled to the integrator, for generating a scaled output of the integrator, the second multiplier being operatively coupled through a delay element; and (d) a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 13

The filter of claim 9 further comprising an upsampling means, operatively coupled to the differencer, for increasing a sample rate of the output of the differencer input to the integrator.

Claim 14

The filter of claim 9 wherein: (a) each post-conditioning means further comprises a third multiplier, operatively coupled to an output of the integrator through at least two delay elements, for generating a scaled output of the integrator; and (b) the summing means is further operatively coupled to the third multiplier, for generating the portion of the post-conditioned digitized signal from the scaled output of the third multiplier.

Claim 15

A filter comprising a plurality of pre-conditioning means for pre-conditioning a digitized signal for subsequent digital signal processing, each pre-conditioning means comprising: (a) an integrator of at least order one; (b) a first, a second, and a third differencer, each operatively coupled to an output of the integrator, each of at least order one, the second differencer being operatively coupled through a delay element, the third differencer being operatively coupled through at least two delay elements; (c) a first, a second, and a third multiplier, operatively coupled to the first, the second, and the third differencer, respectively, for generating scaled outputs of each differencer, respectively; and (d) a summing means, operatively coupled to the each of the multipliers, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the multipliers.

Claim 16

A filter comprising a plurality of pre-conditioning means for pre-conditioning a digitized signal for subsequent digital signal processing, each pre-conditioning means comprising: (a) an integrator of at least order one; (b) a first, a second, and a third differencer, each operatively coupled to an output of the integrator, each of at least order one, the second differencer being operatively coupled through a delay element, the third differencer being operatively coupled through at least two delay elements; (c) a first, a second, and a third multiplier, operatively coupled to the first, the second, and the third differencer, respectively, for generating scaled outputs of each differencer, respectively; and (d) a summing means, operatively coupled to the each of the multipliers, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the multipliers.

Claim 17

A filter comprising a plurality of post-conditioning means for post-conditioning a digitized signal after digital signal processing, each post-conditioning means comprising: (a) a differencer of at least order one; (b) an integrator of at least order one operatively coupled to an output of the differencer; (c) a first, a second, and a third multiplier, operatively coupled to the integrator, for generating scaled outputs of the integrator, the second multiplier being operatively coupled through a delay element, the third multiplier being operatively coupled through at least two delay elements; and (d) a summing means, operatively coupled to each of the multipliers, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the multipliers.

Claim 18

A filter comprising a plurality of post-conditioning means for post-conditioning a digitized signal after digital signal processing, each post-conditioning means comprising: (a) a differencer of at least order one; (b) an integrator of at least order one operatively coupled to an output of the differencer; (c) a first, a second, and a third multiplier, operatively coupled to the integrator, for generating scaled outputs of the integrator, the second multiplier being operatively coupled through a delay element, the third multiplier being operatively coupled through at least two delay elements; and (d) a summing means, operatively coupled to each of the multipliers, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the multipliers.

Claim 19

A communication receiving unit, comprising: (a) a plurality of filtering means for pre-conditioning a digitized signal for subsequent Fourier transformation each filtering means comprising an integrator, at least one differencer, and at least one multiplier operatively coupled together to pre-condition a portion of the digitized signal; and (b) Fourier transforming means, operatively coupled to the plurality of filtering means, for generating a digitized channel signal.

Claim 20

A communication receiving unit, comprising: (a) a plurality of filtering means for pre-conditioning a digitized signal for subsequent Fourier transformation each filtering means comprising an integrator, at least one differencer, and at least one multiplier operatively coupled together to pre-condition a portion of the digitized signal; and (b) Fourier transforming means, operatively coupled to the plurality of filtering means, for generating a digitized channel signal.

Claim 21

The communication unit of claim 14 wherein each filtering means further comprises: (a) the at least one differencer of each filtering means comprises a first and a second differencer, each operatively coupled to an output of the integrator, the second differencer being operatively coupled through a delay element; (b) the at least one multiplier of each filtering means comprises a first and a second multiplier, operatively coupled to the first and the second differencer, respectively, for generating scaled outputs of the first and the second differencer; and (c) each filtering means further comprises a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 22

The communication unit of claim 15 wherein each filtering means further comprises a first and a second decimating means, operatively coupled to the first and the second differencer, respectively, for reducing a sample rate of the output of the integrator input to the first and the second differencer.

Claim 23

The communication unit of claim 15 wherein: (a) each filtering means further comprises: (i) a third differencer operatively coupled to an output of the integrator through at least two delay elements; and (ii) a third multiplier, operatively coupled to the third differencer, for generating a scaled output of the third differencer; and (b) the summing means is further operatively coupled to the third multiplier, for generating the portion of the pre-conditioned digitized signal from the scaled output of the third multiplier.

Claim 24

The communication unit of claim 14 further comprising: (a) input means for intercepting electromagnetic radiation within a frequency band; and (b) digitizing means, operatively coupled to the input means, for digitizing a portion of the intercepted electromagnetic radiation into the digitized signal.

Claim 25

The communication unit of claim 18 wherein the digitizing means comprises: (a) a frequency selection means for selecting a portion of the intercepted electromagnetic radiation; and (b) an analog-to-digital conversion means, operatively coupled to the frequency selection means, for digitizing the selected intercepted electromagnetic radiation portion into a digitized signal.

Claim 26

The communication unit of claim 19 wherein the frequency selection means comprises a frequency translator operatively coupled to a filter that selects intercepted electromagnetic radiation within a particular portion of the frequency band.

Claim 27

The communication unit of claim 20 wherein the frequency translator comprises means for shifting the selected intercepted electromagnetic radiation portion to a predetermined intermediate frequency.

Claim 28

The communication unit of claim 14 further comprising conditioning means, operatively coupled to the Fourier transforming means, for removing undesired signals from the digitized channel signal.

Claim 29

The communication unit of claim 22 wherein the conditioning means comprises means for filtering the digitized channel signal with respect to a signal characteristic selected from the group consisting of optimum selectivity, controlled phase response, and controlled amplitude response.

Claim 30

The communication unit of claim 14 further comprising a detecting means, operatively coupled to the Fourier transforming means, for detecting an information signal within the digitized channel signal.

Claim 31

A communication transmitting unit, comprising: (a) inverse Fourier transforming means for generating a composite digitized signal from a plurality of digitized information signals to be transmitted; and (b) a plurality of filtering means, operatively coupled to the inverse Fourier transforming means, for post-conditioning the composite digitized signal for subsequent transmission, each filtering means comprising an integrator, a differencer, and at least one multiplier operatively coupled together to post-condition a portion of the digitized signal.

Claim 32

A communication transmitting unit, comprising: (a) inverse Fourier transforming means for generating a composite digitized signal from a plurality of digitized information signals to be transmitted; and (b) a plurality of filtering means, operatively coupled to the inverse Fourier transforming means, for post-conditioning the composite digitized signal for subsequent transmission, each filtering means comprising an integrator, a differencer, and at least one multiplier operatively coupled together to post-condition a portion of the digitized signal.

Claim 33

The communication unit of claim 25 wherein: (a) the integrator of each filtering means is operatively coupled to an output of the differencer of each filtering means: (b) the at least one multiplier of each filtering means comprises a first and a second multiplier, operatively coupled to the integrator, for generating scaled outputs of the integrator, the second multiplier being operatively coupled through a delay element; and (c) each filtering means further comprises a summing means, operatively coupled to the first and the second multiplier, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the first and the second multiplier.

Claim 34

The communication unit of claim 26 wherein each filtering means further comprises an upsampler, operatively coupled to the differencer, for increasing a sample rate of the output of the differencer input to the integrator.

Claim 35

The communication unit of claim 26 wherein: (a) each filtering means further comprises a third multiplier, operatively coupled to an output of the integrator through at least two delay elements, for generating a scaled output of the integrator; and (b) the summing means is further operatively coupled to the third multiplier, for generating the portion of the conditioned digitized signal from the scaled output of the third multiplier.

Claim 36

The communication unit of claim 25 further comprising an input means, operatively coupled to the inverse Fourier transforming means, for receiving the plurality of digitized information signals to be transmitted and subsequently providing the plurality of digitized information signals to the inverse Fourier transforming means.

Claim 37

The communication unit of claim 25 further comprising a conditioning means, operatively coupled to the inverse Fourier transforming means, for removing undesired signals from the plurality of digitized information signals prior to the generation of the composite digitized signal.

Claim 38

The communication unit of claim 30 wherein the conditioning means comprises means for filtering each digitized information signal with respect to a signal characteristic selected from the group consisting of optimum selectivity, controlled phase response, and controlled amplitude response.

Claim 39

The communication unit of claim 25 further comprising conversion means, operatively coupled to the plurality of filtering means, for generating a composite analog transmission signal from the post-conditioned portion of the digitized signal of each filtering means.

Claim 40

The communication unit of claim 32 further comprising a frequency selection means, operatively coupled to the conversion means, for selecting a plurality of communication channels to transmit the composite analog transmission signal.

Claim 41

The communication unit of claim 33 wherein the frequency selection means comprises a frequency translator operatively coupled to a filter that selects the plurality of communication channels by selecting a portion of a electromagnetic spectrum to transmit the composite analog transmission signal.

Claim 42

The communication unit of claim 34 wherein the frequency translator comprises means for shifting the composite analog transmission signal to a predetermined intermediate frequency.

Claim 43

A communication receiving unit, comprising: (a) input means for intercepting electromagnetic radiation within a frequency band; (b) digitizing means, coupled to the input means, for digitizing a portion of the intercepted electromagnetic radiation into a digitized signal; (c) a plurality of filtering means, coupled to the digitizing means, for pre-conditioning the digitized signal for subsequent Fourier transformation, each filtering means comprising: (i) an Nth order integrator; (ii) a first, a second, and a third Nth order differencer, each coupled to an output of the integrator, the second differencer being coupled through a first delay element, and the third differencer being coupled through the first and a second delay element; (iii) a first, a second, and a third multiplier, coupled to the first, the second, and the third differencer, respectively, for generating scaled outputs of each differencer, respectively; and (iv) summing means, coupled to the each of the multipliers, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the multipliers; (d) Fourier transforming means, coupled to the plurality of filtering means, for generating a digitized channel signal from the pre-conditioned portions of the digitized signal; (e) conditioning means, coupled to the Fourier transforming means, for removing undesired signals from the digitized channel signal; and (f) detecting means, coupled to the conditioning means, for detecting an information signal within the digitized channel signal.

Claim 44

A communication receiving unit, comprising: (a) input means for intercepting electromagnetic radiation within a frequency band; (b) digitizing means, coupled to the input means, for digitizing a portion of the intercepted electromagnetic radiation into a digitized signal; (c) a plurality of filtering means, coupled to the digitizing means, for pre-conditioning the digitized signal for subsequent Fourier transformation, each filtering means comprising: (i) an Nth order integrator; (ii) a first, a second, and a third Nth order differencer, each coupled to an output of the integrator, the second differencer being coupled through a first delay element, and the third differencer being coupled through the first and a second delay element; (iii) a first, a second, and a third multiplier, coupled to the first, the second, and the third differencer, respectively, for generating scaled outputs of each differencer, respectively; and (iv) summing means, coupled to the each of the multipliers, for generating a portion of the pre-conditioned digitized signal from the scaled outputs of the multipliers; (d) Fourier transforming means, coupled to the plurality of filtering means, for generating a digitized channel signal from the pre-conditioned portions of the digitized signal; (e) conditioning means, coupled to the Fourier transforming means, for removing undesired signals from the digitized channel signal; and (f) detecting means, coupled to the conditioning means, for detecting an information signal within the digitized channel signal.

Claim 45

A communication transmitting unit, comprising: (a) input means for receiving a plurality of digitized information signals to be transmitted; (b) conditioning means, coupled to the input means, for removing undesired signals from the plurality of digitized information signals; (c) inverse Fourier transforming means, coupled to the conditioning means, for generating a plurality of digitized signals from the plurality of digitized information signals; (d) a plurality of filtering means, coupled to the inverse Fourier transforming means, for post-conditioning the plurality of digitized signals for subsequent transmission, each filtering means comprising: (i) an Nth order differencer; (ii) an Nth order integrator coupled to an output of the differencer; (iii) a first, a second, and a third multiplier, coupled to the integrator, for generating scaled outputs of the integrator, the second multiplier being coupled through a first delay element, and the third multiplier being coupled through the first and a second delay element; and (iv) summing means, coupled to each of the multipliers, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the multipliers; (e) conversion means, coupled to the plurality of filtering means, for generating a composite analog transmission signal from the portion of the post-conditioned digitized signal of each filtering means; and (f) frequency selection means, coupled to the conversion means, for selecting a communication channel to transmit the composite analog transmission signal.

Claim 46

A communication transmitting unit, comprising: (a) input means for receiving a plurality of digitized information signals to be transmitted; (b) conditioning means, coupled to the input means, for removing undesired signals from the plurality of digitized information signals; (c) inverse Fourier transforming means, coupled to the conditioning means, for generating a plurality of digitized signals from the plurality of digitized information signals; (d) a plurality of filtering means, coupled to the inverse Fourier transforming means, for post-conditioning the plurality of digitized signals for subsequent transmission, each filtering means comprising: (i) an Nth order differencer; (ii) an Nth order integrator coupled to an output of the differencer; (iii) a first, a second, and a third multiplier, coupled to the integrator, for generating scaled outputs of the integrator, the second multiplier being coupled through a first delay element, and the third multiplier being coupled through the first and a second delay element; and (iv) summing means, coupled to each of the multipliers, for generating a portion of the post-conditioned digitized signal from the scaled outputs of the multipliers; (e) conversion means, coupled to the plurality of filtering means, for generating a composite analog transmission signal from the portion of the post-conditioned digitized signal of each filtering means; and (f) frequency selection means, coupled to the conversion means, for selecting a communication channel to transmit the composite analog transmission signal.

Claim 49

The method of claim 38: (a) wherein the step of taking the difference comprises taking a first difference of the integrated signal and taking a second difference of delayed integrated signal; (b) wherein the step of multiplying comprises multiplying the first and the second differenced integrated signals by scale factors; and (c) further comprising the step of summing the first and the second multiplied integrated signals into a composite signal; and (d) wherein the generating step comprises generating the digitized channel signal by Fourier transforming the composite signal.

Claim 50

The method of claim 38 further comprises the steps of: (a) intercepting electromagnetic radiation within a frequency band; and (b) selecting a portion of the intercepted electromagnetic radiation; and (c) digitizing the selected portion of the intercepted electromagnetic radiation into the digitized signal.

Claim 51

The method of claim 38 further comprises the step of removing undesired signals from the digitized channel signal.

Claim 52

The method of claim 38 further comprises the step of detecting an information signal within the digitized channel signal.

Claim 55

The method of claim 43: (a) wherein the step of multiplying comprises multiplying the integrated signal to generate a first multiplied integrated signal and multiplying a delayed integrated signal to generate a second multiplied integrated signal; and (b) further comprising the step of summing the first and the second multiplied integrated signals into a composite integrated signal.

Claim 56

The method of claim 43 further comprising the step of removing undesired signals from the plurality of digitized information signals prior to the generation of the composite digitized signal.

Claim 57

The method of claim 44 further comprising the step of generating a composite analog transmission signal from the composite integrated signal.

Claim 58

The method of claim 46 further comprising the step of selecting a plurality of communication channels to transmit the composite analog transmission signal.

Claim 59

A communication receiving unit, comprising: (a) an analog-to-digital conversion means for digitizing a selected portion of an input frequency band; (b) commutating means, operatively coupled to the analog-to-digital conversion means, for subdividing the digitized portion of the input frequency band into the plurality of digitized signal portions; (c) discrete Fourier transforming means, operatively coupled to the commutating means, for generating a plurality of digitized channel signals by discrete Fourier transforming the plurality of digitized signal portions, the discrete Fourier transforming means comprising conditioning means for pre-conditioning the plurality of digitized signal portions with a modified cascaded integrator comb filter; and (d) a detecting means, operatively coupled to the discrete Fourier transforming means, for detecting at least two information signals from the plurality of digitized channel signals.

Claim 60

A communication receiving unit, comprising: (a) an analog-to-digital conversion means for digitizing a selected portion of an input frequency band; (b) commutating means, operatively coupled to the analog-to-digital conversion means, for subdividing the digitized portion of the input frequency band into the plurality of digitized signal portions; (c) discrete Fourier transforming means, operatively coupled to the commutating means, for generating a plurality of digitized channel signals by discrete Fourier transforming the plurality of digitized signal portions, the discrete Fourier transforming means comprising conditioning means for pre-conditioning the plurality of digitized signal portions with a modified cascaded integrator comb filter; and (d) a detecting means, operatively coupled to the discrete Fourier transforming means, for detecting at least two information signals from the plurality of digitized channel signals.

Claim 61

The communication unit of claim 48 further comprising a frequency selection means, operatively coupled to the analog-to-digital conversion means, for intercepting and providing the selected portion of the input frequency band.

Claim 62

The communication unit of claim 49 wherein the frequency selection means comprises a filter that selects a portion of an electrical signal which represents the intercepted electromagnetic radiation within a particular portion of the frequency band.

Claim 63

The communication unit of claim 49 wherein the frequency selection means comprises a frequency translator operatively coupled to a filter that selects a portion of an electrical signal which represents the intercepted electromagnetic radiation within a particular portion of the frequency band.

Claim 64

The communication unit of claim 48 wherein the conditioning means comprises means for filtering each digitized signal portion with respect to a signal characteristic selected from the group consisting of optimum selectivity, controlled phase response, and controlled amplitude response.

Claim 65

The communication unit of claim 48 wherein each information signal conforms with a signal coding and channelization standard selected from the group consisting of frequency division multiple access, time division multiple access, and frequency hopping code division multiple access.

Claim 66

A communication transmitting unit, comprising: (a) inverse discrete Fourier transforming means for generating a plurality of digitized signals by inverse discrete Fourier transforming a plurality of input digitized information signals, the inverse discrete Fourier transforming means comprising conditioning means for post-conditioning the plurality of digitized signals with a modified cascaded integrator comb filter; (b) commutating means, operatively coupled to the inverse discrete Fourier transforming means, for combining portions of the plurality of digitized signals into a composite digitized signal; (c) digital-to-analog conversion means, operatively coupled to the commutating means, for generating a composite analog transmission signal from the composite digitized signal; and (d) transmitting means, operatively coupled to the digital-to-analog conversion means, for transmitting the composite analog transmission signal over a frequency band.

Claim 67

A communication transmitting unit, comprising: (a) inverse discrete Fourier transforming means for generating a plurality of digitized signals by inverse discrete Fourier transforming a plurality of input digitized information signals, the inverse discrete Fourier transforming means comprising conditioning means for post-conditioning the plurality of digitized signals with a modified cascaded integrator comb filter; (b) commutating means, operatively coupled to the inverse discrete Fourier transforming means, for combining portions of the plurality of digitized signals into a composite digitized signal; (c) digital-to-analog conversion means, operatively coupled to the commutating means, for generating a composite analog transmission signal from the composite digitized signal; and (d) transmitting means, operatively coupled to the digital-to-analog conversion means, for transmitting the composite analog transmission signal over a frequency band.

Claim 68

The communication unit of claim 54 wherein each information signal conforms with a signal coding and channelization standard selected from the group consisting of frequency division multiple access, time division multiple access, and frequency hopping code division multiple access.

Claim 69

The communication unit of claim 54 wherein the conditioning means comprises means for filtering each digitized signal with respect to a signal characteristic selected from the group consisting of optimum selectivity, controlled phase response, and controlled amplitude response.

Claim 70

The communication unit of claim 54 further comprising a frequency selection means, operatively coupled to the digital-to-analog conversion means and the transmitting means, for selecting the portion of the frequency band that the composite analog transmission signal is to be transmitted.

Claim 71

The communication unit of claim 57 wherein the frequency selection means comprises a filter that selects a portion of an electrical signal which represents electromagnetic radiation within a particular portion of the frequency band.

Claim 72

The communication unit of claim 57 wherein the frequency selection means comprises a frequency translator operatively coupled to a filter that selects a portion of an electrical signal which represents electromagnetic radiation within a particular portion of the frequency band.