United States Patent (19)
`United States Patent [19]
`Schiltz et al.
`Schiltz et al.
`
`11111111111111111111111111111,1!1151,11113914191 111111111111111111111111111
`
`US005339459A
`5,339,459
`5,339,459
`11
`Patent Number:
`[11] Patent Number:
`Aug. 16, 1994
`45) Date of Patent:
`[45] Date of Patent: Aug. 16, 1994
`
`(56)
`[56]
`
`3,602,825 8/1971. Senior ..............
`
`-
`
`-
`
`- - -
`
`- -
`
`-
`
`- - - - - - 307/352
`
`(54) HIGHSPEEDSAMPLE AND HOLD CIRCUIT
`[54] HIGH SPEED SAMPLE AND HOLD CIRCUIT
`AND RADIO CONSTRUCTED THEREWITH
`AND RADIO CONSTRUCTED THEREWITH
`(75) Inventors: Thomas E. Schiltz, Chandler; Carl R.
`[75]
`Inventors: Thomas E. Schiltz, Chandler; Carl R.
`Nuckolls, Fountain Hills, both of
`Nuckolls, Fountain Hills, both of
`Ariz.
`Ariz.
`73) Assignee: Motorola, Inc., Schaumburg, Ill.
`[73] Assignee: Motorola, Inc., Schaumburg, Ill.
`(21) Appl. No.: 985,477
`[21] Appl. No.: 985,477
`22 Filed:
`Dec. 3, 1992
`[22] Filed:
`Dec. 3, 1992
`51) Int. Cl......................... H04B 1/28; H03K 5/159
`[51] Int. C1 5
` HO4B 1/28; HO3K 5/159
`152 U.S. Cl. .................................... 455/333; 455/313;
`[52] U.S. Cl.
` 455/333; 455/313;
`455/318; 307/353
`455/318;307/353
`58 Field of Search ............... 455/313, 318, 323, 319,
`[58] Field of Search
` 455/313, 318, 323, 319,
`455/343,333,334, 316; 307/352, 353; 328/151
`455/343, 333, 334, 316; 307/352, 353; 328/151
`References Cited
`References Cited
`U.S. PATENT DOCUMENTS
`U.S. PATENT DOCUMENTS
`Re. 32,314 12/1986 Gittins et al.
`Re. 32,314 12/1986 Gittins et al. ....................... 455/263
` 455/263
`3,602,825 8/1971 Senior
` 307/352
`4,066,919 1/1978 Huntington ......................... 307/353
`4,066,919 1/1978 Huntington
` 307/353
`4,370,572 1/1983 Cosand et al.
`4,370,572
`/1983 Cosand et al. .......
`... 307/353
` 307/353
`4,389,579 6/1983 Stein
` 307/353
`4.389,579 6/1983 Stein .....................
`... 307/353
`4,612,464 9/1986 Ishikawa et al.
` 307/352
`4,612,464 9/1986 Ishikawa et al. .
`... 307/352
`4,801,823 1/1989 Yokoyama
`4,801,823 1/1989 Yokoyama ...........
`... 307/353
` 307/353
`4,806,790 2/1989 Sone
` 307/353
`4,806,790 2/1989 Sone .....................
`... 307/353
`4,910,752 3/1990 Yester, Jr. et al.
`4,910,752 3/1990 Yester, Jr. et al. .
`... 455/343
` 455/343
`4,922,452 5/1990 Larsen et al.
` 365/45
`4,922,452 5/1990 Larsen et al. ........
`4,970,703 11/1990 Hariharan et al.
` 367/138
`4,970,703 11/1990 Hariharan et al. ...
`... 367/138
`5,017,924 5/1991 Guiberteau et al.
` 342/195
`5,017,924 5/1991 Guiberteau et al. ................ 342/195
`OTHER PUBLICATIONS
`OTHER PUBLICATIONS
`An article entitled "Accurately Model Unbiased FETs
`An article entitled "Accurately Model Unbiased FETs
`for Monolithic Switches', by C. Kermarrec et al. of
`for Monolithic Switches", by C. Kermarrec et al. of
`Tachonics Corp., from Microwaves & RF Jun. 1989.
`Tachonics Corp., from Microwaves & RF, Jun. 1989.
`An article entitled “Waveform Sampling with Schottky
`An article entitled "Waveform Sampling with Schottky
`Diodes' Hewlett Packard Components Application Bulle
`Diodes" Hewlett Packard Components Application Bulle-
`tin 16, 5952-9818 (Nov. 1976).
`tin 16, 5952-9818 (Nov. 1976).
`An article entitled "A 1-GHz 6-bit ADC System” by
`An article entitled "A 1-GHz 6-bit ADC System" by
`Ken Poulton et al., IEEE Journal of Solid-State Circuits,
`Ken Poulton et al., IEEE Journal of Solid-State Circuits,
`vol. SC-22, No. 6, Dec. 1987, pp. 962-969.
`vol. SC-22, No. 6, Dec. 1987, pp. 962-969.
`An article entitled "Characterization of Microwave
`An article entitled "Characterization of Microwave
`Integrated Circuits. Using an Optical Phase-Locking
`Integrated Circuits Using an Optical Phase-Locking
`and Sampling System', by H-L. A. Hung et al. of
`and Sampling System", by H-L. A. Hung et al. of
`COMSAT Laboratories, Clarksburg, Md., IEEE
`COMSAT Laboratories, Clarksburg, Md., IEEE
`MTT-S Digest, 1991, pp. 507–510.
`MTT-S Digest, 1991, pp. 507-510.
`
`- - - - - 365/45
`
`An article entitled "Computer-Aided Noise analysis of
`An article entitled "Computer-Aided Noise analysis of
`MESFET and HEMT Mixers', by V. Rizzoli et al.,
`MESFET and HEMT Mixers", by V. Rizzoli et al.,
`IEEE Transactions on Microwave Theory and Techniques,
`IEEE Transactions on Microwave Theory and Techniques,
`vol. 37, No. 9, Sep. 1989, pp. 1401-1410.
`vol. 37, No. 9, Sep. 1989, pp. 1401-1410.
`An article entitled "Novel GaAs FET Phase Detector
`An article entitled "Novel GaAs FET Phase Detector
`Operable to Ka Band'T. Takano et al. Fujitsu Labora
`Operable to Ka Band" T. Takano et al. Fujitsu Labora-
`tories Ltd., Kawasaki, Japan, IEEE MTTS Digest,
`tories Ltd., Kawasaki, Japan, IEEE MTT-S Digest,
`1984, pp. 381-383.
`1984, pp. 381-383.
`An article entitled "130 GHz GaAs Monolithic Inte
`An article entitled "130 GHz GaAs Monolithic Inte-
`grated Circuit Sampling Head', by R. A. Marsland et
`grated Circuit Sampling Head", by R. A. Marsland et
`al. of Edward L. Ginzton Laboratory, Stanford Univer
`al. of Edward L. Ginzton Laboratory, Stanford Univer-
`sity, Stanford, Calif., 1989 American Institute of Physics,
`sity, Stanford, Calif., 1989 American Institute of Physics,
`Appl. Phy. Lett. 55(6), 7 Aug. 1989, pp. 592–594.
`Appl. Phy. Lett. 55(6), 7 Aug. 1989, pp. 592-594.
`An article entitled "RF Sampling Gates: a brief re
`An article entitled "RF Sampling Gates: a brief re-
`view', by N. P. Akers et al., IEEProceedings, vol. 133,
`view", by N. P. Akers et al., IEE Proceedings, vol. 133,
`Pt. A. No. 1, Jan. 1986, pp. 45-49.
`Pt. A. No. 1, Jan. 1986, pp. 45-49.
`(List continued on next page.)
`(List continued on next page.)
`Primary Examiner-Reinhard J. Eisenzopf
`Primary Examiner—Reinhard J. Eisenzopf
`Assistant Examiner-Nguyen Vo
`Assistant Examiner—Nguyen V o
`Attorney, Agent, or Firm-Frederick M. Fliegel; Robert
`Attorney, Agent, or Firm—Frederick M. Fliegel; Robert
`M. Handy
`M. Handy
`ABSTRACT
`57)
`[57]
`ABSTRACT
`A sample and hold circuit is formed within an inte
`A sample and hold circuit is formed within an inte-
`grated circuit and has a small, substantially linear hold
`grated circuit and has a small, substantially linear hold
`capacitance. The circuit includes a sampling switch, a
`capacitance. The circuit includes a sampling switch, a
`hold capacitor, and a buffer amplifier. The buffer ampli
`hold capacitor, and a buffer amplifier. The buffer ampli-
`fier includes a common drain FET and a constant cur
`fier includes a common drain FET and a constant cur-
`rent source FET. The common drain FET provides an
`rent source FET. The common drain FET provides an
`input which couples to the hold capacitor. The constant
`input which couples to the hold capacitor. The constant
`current FET isolates the source of the common drain
`current FET isolates the source of the common drain
`FET from ground. The sample and hold circuit may be
`FET from ground. The sample and hold circuit may be
`used as a wide bandwidth mixer. In a radio application,
`used as a wide bandwidth mixer. In a radio application,
`a pulse generator provides a stream of pulses in which
`a pulse generator provides a stream of pulses in which
`the sampling rate times an integer number equals the RF
`the sampling rate times an integer number equals the RF
`frequency minus the IF frequency. The width of the
`frequency minus the IF frequency. The width of the
`sampling pulse is less than the period of an RF signal. In
`sampling pulse is less than the period of an RF signal. In
`an oscillator application, the sample and hold circuit
`an oscillator application, the sample and hold circuit
`operates as a mixer in a frequency multiplying phase
`operates as a mixer in a frequency multiplying phase
`locked loop.
`locked loop.
`
`17 Claims, 3 Drawing Sheets
`17 Claims, 3 Drawing Sheets
`
`
`
`68
`
`784
`
`80
`
`82
`
`26-1
`
`96
`TRANSMISSIO
`LINE
`
`88
`
` 1F-±
`
`86'
`
`80
`
`807
`
`4.- 92
`
`
`
`90 1
`
`80
`
`102
`
`104,
`
`97
`
`RANSMISSION
`LINE
`
`98
`
`7
`
`1084.
`
`112°,6_
`
`80
`
`80
`
`-112
`
`100
`
`110
`
`4
`
`44
`
`84
`
`94
`
`66
`
`72
`
`I22-
`
`11
`
`116
`
`120
` IF1
`80
`
`124
`
`TCL, Hisense & ZyXel
`Ex. 1006
`Page 1
`
`

`

`5,339,459
`5,339,459
`Page 2
`Page 2
`
`OTHER PUBLICATIONS
`OTHER PUBLICATIONS
`An article entitled "Sampling for Oscilloscopes and
`An article entitled "Sampling for Oscilloscopes and
`Other RF Systems: Dc through X-Band”, by W. M.
`Other RF Systems: Dc through X-Band", by W. M.
`Grove, IEEE Transactions on Microwave Theory and
`Grove, IEEE Transactions on Microwave Theory and
`Techniques, vol. MTT-14, No. 12, Dec. 1966, pp.
`Techniques, vol. MTT-14, No. 12, Dec. 1966, pp.
`629–635.
`629-635.
`An article entitled "Sampling Loops Lock Sources to
`An article entitled "Sampling Loops Lock Sources to
`23 GHz", Microwaves & RF, Sep.1990.
`23 GHz", Microwaves & RF, Sep. 1990.
`An article entitled "Subharmonic Sampling for the
`An article entitled "Subharmonic Sampling for the
`Measurement of Short-Term Stability of Microwave
`Measurement of Short-Term Stability of Microwave
`
`Oscillators' by N. D. Faulkner et al., IEEE Transac
`Oscillators" by N. D. Faulkner et al., IEEE Transac-
`tions on Instrumentation and Measurement, vol. IM-32,
`tions on Instrumentation and Measurement, vol. IM-32,
`No. 1, Mar. 1983, pp. 208-213.
`No. 1, Mar. 1983, pp. 208-213.
`An article entitled "Sub-Nanosecond Single-Shot Dig
`An article entitled "Sub-Nanosecond Single-Shot Dig-
`itizing Using the HP 54111D', Hewlett Packard Product
`itizing Using the HP 54111D", Hewlett Packard Product
`Note HP54111D-1, Mar. 1988.
`Note HP 54111D-1, Mar. 1988.
`An article entitled “2.4 GHz MESFET Sampler', by H.
`An article entitled "2.4 GHz MESFET Sampler", by H.
`Hafdallah et al., Institut d'Electronique Fondamentale,
`Hafdallah et al., Institut d'Electronique Fondamentale,
`Universite Paris, France, 10th Dec. 1987.
`Universite Paris, France, 10th Dec. 1987.
`An article entitled "Readout', Electronic Engineering,
`An article entitled "Readout", Electronic Engineering,
`Mar. 1987, pp. 77-79.
`Mar. 1987, pp. 77-79.
`
`TCL, Hisense & ZyXel
`Ex. 1006
`Page 2
`
`

`

`U.S. Patent
`U.S. Patent
`
`Aug. 16, 1994
`Aug. 16, 1994
`
`Sheet 1 of 3
`Sheet 1 of 3
`
`5,339,459
`5,339,459
`
`12
`
`LOW
`NOISE
`AMP
`
`14
`
`
`
`
`
`
`
`
`
`
`
`RF
`
`RE
`
`16
`
`20
`
`LOW
`NOISE
`AMP
`
`I/8
`
`IMAGE
`FILTER
`
`24
`
`IMAGE
`FILTER
`
`22
`
`fi
`10
`
`30
`
`301
`
`Af7G 7
`1
`FIG_
`
`26
`1
`HIGH SPEED
`HIGH SPEED
`SAMPLE AND
`SAMPLE AND
`HOLD CIRCUIT
`HOLD CIRCUIT
`
`
`
`F
`
`28
`28
`DETECTOR I
`
`IMPULSE
`GENERATOR
`
`34
`
`LVEX(21,
`32
`32
`
`PULSE
`GENERATOR
`
`Gefior
`
`38j
`38
`
`
`
`S
`
`
`
`40
`40
`
`IMPULSE
`GENERATOR
`
` J FREQUENCY
`DIVIDER
`
`42
`
`
`
`f
`36
`36
`
`Af7G 2
`.2
`FIG_
`
`44
`44
`HIGH SPEED
`HIGH SPEED
`SAMPLE AND
`SAMPLE AND
`HOLD CIRCUIT
`HOLD CIRCUIT
`
`r,
`
`46
`
`LOOP
`FILTER
`FILTER
`
`
`
`
`
`48iLOOP
`i50 DIELECTRIC
`
`50 DIELECTRIC
`RESONATOR
`RESONATOR
`OSCILLATOR
`OSCILLATOR
`
`
`
`POWER
`1_1.
`RE
`DIVIDER
`
`
`
`52
`52
`
`TCL, Hisense & ZyXel
`Ex. 1006
`Page 3
`
`

`

`U.S. Patent
`U.S. Patent
`
`Aug. 16, 1994
`Aug. 16, 1994
`
`Sheet 2 of 3
`Sheet 2 of 3
`
`5,339,459
`5,339,459
`
`60
`
`60
`
`58
`
`58
`54
`
`54
`
`54
`
`56
`
`.F-7 -4G.. S
`
`56
`
`54
`
`• •
`
`DC
`
`1/T
`
`777G 4
`FIG_
`4
`
`DC
`DC
`
`• •
`
`64 62 62
`64 62 62
`A).) )
`
`• 4 b ,
`
`....-'
`Fs
`
`• •
`
`
`
`TCL, Hisense & ZyXel
`Ex. 1006
`Page 4
`
`

`

`U.S. Patent
`
`Aug. 16, 1994
`t'66T `91 '$11v
`
`Sheet 3 of 3
`£ Jo £ PaLIS
`
`5,339,459
`
`
`
`
`110
`
`114
`
`# II
`
`106
`
`h
`
`7
`80
`
`102
`
`104
`
`98
`
`97
`TRANSMISSION
`LINE
`
`ENIT
`
`NOISSIWSNW8||
`
`r
`
`68
`
`-r
`
`•
`
`96
`TRANSMISSION I
`LINE
`
`•
`
`76
`1
`
`74
`
`ff/
`
`108
`
`7
`80
`
`100
`
`112
`
`,
`
`118
`
`116
`
`72
`
`122.-
`
`120
`
`7
`80
`
`124
`
`
`.1
`
`I
`86
`
`88
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`h
`
`I
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`
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`
`192
`
`90
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`
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`44
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`,
`84
`
`5
`
`FIG_
`
`Gº ~ º) Z, AZ
`
`TCL, Hisense & ZyXel
`Ex. 1006
`Page 5
`
`

`

`1
`1
`
`5,339,459
`5,339,459
`
`HIGH SPEED SAMPLE AND HOLD CIRCUIT AND
`HIGH SPEED SAMPLE AND HOLD CIRCUIT AND
`RADIO CONSTRUCTED THEREWITH
`RADIO CONSTRUCTED THEREWITH
`
`2
`2
`SUMMARY OF THE INVENTION
`SUMMARY OF THE INVENTION
`Accordingly, it is an advantage of the present inven
`Accordingly, it is an advantage of the present inven-
`tion that an improved radio is provided.
`tion that an improved radio is provided.
`Another advantage is that the present invention pro
`TECHNICAL FIELD OF THE INVENTION
`s
`5 Another advantage is that the present invention pro-
`TECHNICAL FIELD OF THE INVENTION
`vides a radio which uses a sample and hold circuit as a
`vides a radio which uses a sample and hold circuit as a
`The present invention relates generally to high speed
`The present invention relates generally to high speed
`mixer, which does not require the generation of a LO
`mixer, which does not require the generation of a LO
`electronic circuits. More specifically, the present inven
`signal near an RF frequency, and which uses only a few
`electronic circuits. More specifically, the present inven-
`signal near an RF frequency, and which uses only a few
`tion relates to a high speed sample and hold circuit and
`low-power components.
`tion relates to a high speed sample and hold circuit and
`low-power components.
`to radios which use such a circuit as a mixer.
`Another advantage is that the present invention pro
`to radios which use such a circuit as a mixer.
`10 Another advantage is that the present invention pro-
`vides an oscillating signal generation circuit which pro
`vides an oscillating signal generation circuit which pro-
`BACKGROUND OF THE INVENTION
`BACKGROUND OF THE INVENTION
`duces a relatively high frequency output signal locked
`duces a relatively high frequency output signal locked
`Conventional radios which detect high frequency RF
`to a relatively low frequency reference signal using only
`Conventional radios which detect high frequency RF
`to a relatively low frequency reference signal using only
`signals, above 300 MHz for example, or otherwise gen
`a few low-power components.
`signals, above 300 MHz for example, or otherwise gen-
`a few low-power components.
`erate high frequency signals often consume great
`Another advantage of the present invention is that an
`erate high frequency signals often consume great
`15
`15 Another advantage of the present invention is that an
`amounts of power, require a large amount of space,
`improved sample and hold circuit is provided.
`amounts of power, require a large amount of space,
`improved sample and hold circuit is provided.
`require excessive amounts of individual alignment, are
`Another advantage is that the present invention pro
`require excessive amounts of individual alignment, are
`Another advantage is that the present invention pro-
`excessively expensive, and suffer from reduced reliabil
`vides a sample and hold circuit which exhibits a rela
`excessively expensive, and suffer from reduced reliabil-
`vides a sample and hold circuit which exhibits a rela-
`ity. These problems result, at least in part, from the
`tively linear hold capacitance when operated at high
`ity. These problems result, at least in part, from the
`tively linear hold capacitance when operated at high
`generation of local oscillator or other oscillation signals
`RF frequencies.
`generation of local oscillator or other oscillation signals
`20
`20 RF frequencies.
`at high frequencies.
`Another advantage is that the present invention pro
`at high frequencies.
`Another advantage is that the present invention pro-
`For example, frequencies of signals used in these
`vides a single sample and hold circuit which may be
`For example, frequencies of signals used in these
`vides a single sample and hold circuit which may be
`applications must often be multiplied by factors in the
`used as either a phase detector or a mixer.
`applications must often be multiplied by factors in the
`used as either a phase detector or a mixer.
`The above and other advantages of the present inven
`range of 25-200. One conventional technique for ac
`range of 25-200. One conventional technique for ac-
`The above and other advantages of the present inven-
`tion are carried out in one form by an improved radio
`complishing the multiplication is through the use of a
`25
`complishing the multiplication is through the use of a
`25 tion are carried out in one form by an improved radio
`having a receiver capable of receiving a wideband RF
`cascade of step recovery diode multipliers, each of
`having a receiver capable of receiving a wideband RF
`cascade of step recovery diode multipliers, each of
`signal. The radio includes an antenna that supplies an
`which multiply by a factor of around 2-15. Such multi
`signal. The radio includes an antenna that supplies an
`which multiply by a factor of around 2-15. Such multi-
`RF signal exhibiting an RF frequency. A sample and
`pliers can require up to 16 cubic inches in volume and
`RF signal exhibiting an RF frequency. A sample and
`pliers can require up to 16 cubic inches in volume and
`hold circuit has a sample input that couples to the an
`consume an excess of 2 Watt of power. Another con
`hold circuit has a sample input that couples to the an-
`consume an excess of 2 Watt of power. Another con-
`tenna. A hold output of the sample and hold circuit
`ventional technique for accomplishing the multiplica
`30
`30 tenna. A hold output of the sample and hold circuit
`ventional technique for accomplishing the multiplica-
`supplies an IF signal. A pulse generator has an output
`tion is through the use of a phase locked loop which
`supplies an IF signal. A pulse generator has an output
`tion is through the use of a phase locked loop which
`which couples to a control input of the sample and hold
`requires less space but still requires high power, high
`which couples to a control input of the sample and hold
`requires less space but still requires high power, high
`circuit. The pulse generator is configured to produce a
`speed frequency dividers.
`circuit. The pulse generator is configured to produce a
`speed frequency dividers.
`stream of pulses at a sampling rate less than the RF
`Both of these techniques produce narrow band out
`stream of pulses at a sampling rate less than the RF
`Both of these techniques produce narrow band out-
`frequency. Moreover, the pulse generator is configured
`35
`put signals. With a cascade of step recovery diodes,
`35 frequency. Moreover, the pulse generator is configured
`put signals. With a cascade of step recovery diodes,
`so that each of the pulses has a pulse width substantially
`so that each of the pulses has a pulse width substantially
`each cascaded stage must be carefully aligned for opera
`each cascaded stage must be carefully aligned for opera-
`less than a period for the RF signal.
`less than a period for the RF signal.
`tion at a single output frequency, and filters in each
`tion at a single output frequency, and filters in each
`The above and other advantages of the present inven
`The above and other advantages of the present inven-
`stage must be individually tuned to reject undesired
`stage must be individually tuned to reject undesired
`tion are carried out in another form by an improved
`tion are carried out in another form by an improved
`harmonics. With a phase locked loop, the tuning range
`harmonics. With a phase locked loop, the tuning range
`high speed sample and hold circuit. The sample and
`40 high speed sample and hold circuit. The sample and
`of a voltage controlled oscillator limits the frequency
`of a voltage controlled oscillator limits the frequency
`hold circuit includes a sampling switch that has an input
`hold circuit includes a sampling switch that has an input
`range producible, and this tuning range is typically
`range producible, and this tuning range is typically
`for receiving a signal to be sampled. A hold capacitor
`for receiving a signal to be sampled. A hold capacitor
`minimized to reduce phase noise. The need for individ
`minimized to reduce phase noise. The need for individ-
`couples to an output of the sampling switch. A first
`ual alignment in devices which operate at high frequen
`couples to an output of the sampling switch. A first
`ual alignment in devices which operate at high frequen-
`transistor is configured in a common drain circuit ar
`transistor is configured in a common drain circuit ar-
`cies drives up costs by introducing costly manufactur
`cies drives up costs by introducing costly manufactur-
`rangement and has a gate that couples to the sampling
`45
`45 rangement and has a gate that couples to the sampling
`ing steps and by introducing opportunities for mistakes
`ing steps and by introducing opportunities for mistakes
`switch output. A second transistor is configured as a
`switch output. A second transistor is configured as a
`and errors in workmanship.
`and errors in workmanship.
`substantially constant current source. The second tran
`substantially constant current source. The second tran-
`As discussed below, sample and hold circuits may be
`As discussed below, sample and hold circuits may be
`sistor couples to a source of the first transistor.
`sistor couples to a source of the first transistor.
`used in solving at least some of the problems posed by
`used in solving at least some of the problems posed by
`radios which operate at high frequency. An extensive
`BRIEF DESCRIPTION OF THE DRAWINGS
`50 BRIEF DESCRIPTION OF THE DRAWINGS
`radios which operate at high frequency. An extensive
`50
`body of technology has developed around utilizing
`A more complete understanding of the present inven
`body of technology has developed around utilizing
`A more complete understanding of the present inven-
`sample and hold circuits in the digital reconstruction of
`tion may be derived by referring to the detailed descrip
`sample and hold circuits in the digital reconstruction of
`tion may be derived by referring to the detailed descrip-
`analog signals. Since the majority of this technology
`tion and claims when considered in connection with the
`analog signals. Since the majority of this technology
`tion and claims when considered in connection with the
`requires sampling to occur at a rate which is typically
`Figures, wherein like reference numbers refer to similar
`requires sampling to occur at a rate which is typically
`Figures, wherein like reference numbers refer to similar
`greater than twice the frequency of the signal being
`items throughout the Figures, and:
`greater than twice the frequency of the signal being
`55 items throughout the Figures, and:
`sampled, a need has always existed for higher speed
`FIG. 1 shows a block diagram of a radio constructed
`sampled, a need has always existed for higher speed
`FIG. 1 shows a block diagram of a radio constructed
`sample and hold circuits.
`in accordance with the teaching of the present inven
`sample and hold circuits.
`in accordance with the teaching of the present inven-
`Nevertheless, the performance of conventional sam
`Nevertheless, the performance of conventional sam-
`tion;
`tion;
`ple and hold circuits operating at high frequency micro
`FIG. 2 shows a block diagram of an oscillating signal
`ple and hold circuits operating at high frequency micro-
`FIG. 2 shows a block diagram of an oscillating signal
`wave RF rates has remained poor. For example, acqui
`generation circuit constructed in accordance with the
`wave RF rates has remained poor. For example, acqui-
`60 generation circuit constructed in accordance with the
`sition time and acquisition accuracy have often been too
`teaching of the present invention;
`sition time and acquisition accuracy have often been too
`teaching of the present invention;
`FIG. 3 shows an exemplary spectral diagram depict
`poor to permit the use of sample and hold circuits at
`poor to permit the use of sample and hold circuits at
`FIG. 3 shows an exemplary spectral diagram depict-
`higher RF frequencies in any application other than
`ing a sample pulse spectrum and an RF spectrum;
`higher RF frequencies in any application other than
`ing a sample pulse spectrum and an RF spectrum;
`those requiring only very narrow output bandwidths,
`FIG. 4 shows an exemplary spectral diagram depict
`those requiring only very narrow output bandwidths,
`FIG. 4 shows an exemplary spectral diagram depict-
`ing the convolution of the sample pulse and RF spectra
`such as phase detector applications. Moreover, non
`such as phase detector applications. Moreover, non-
`65
`65 ing the convolution of the sample pulse and RF spectra
`linearities in critical parameters, such as hold capaci
`of FIG. 3; and
`linearities in critical parameters, such as hold capaci-
`of FIG. 3; and
`tance, become severe handicaps at higher RF frequen
`FIG. 5 shows a schematic diagram of a sample and
`tance, become severe handicaps at higher RF frequen-
`FIG. 5 shows a schematic diagram of a sample and
`hold circuit.
`cies.
`cies.
`hold circuit.
`
`TCL, Hisense & ZyXel
`Ex. 1006
`Page 6
`
`

`

`5,339,459
`5,339,459
`4
`4
`3
`3
`ator 30 includes an oscillation signal source, such as a
`ator 30 includes an oscillation signal source, such as a
`DETAILED DESCRIPTION OF THE
`DETAILED DESCRIPTION OF THE
`voltage controlled crystal oscillator (VCXO) 32. The
`voltage controlled crystal oscillator (VCXO) 32. The
`PREFERRED EMBODIMENTS
`PREFERRED EMBODIMENTS
`frequency of oscillator 32 (f) may be controlled exter
`frequency of oscillator 32 (fs) may be controlled exter-
`nally (not shown) within a frequency range that is eas
`FIG. 1 shows a block diagram of a radio 10 which
`nally (not shown) within a frequency range that is eas-
`FIG. 1 shows a block diagram of a radio 10 which
`ily, reliably, and inexpensively achievable. In the exam
`converts one or more RF signals into an IF signal and
`ily, reliably, and inexpensively achievable. In the exam-
`converts one or more RF signals into an IF signal and 5
`ple embodiment of the present invention, oscillator 32
`then into a baseband signal. Radio 10 includes an an
`ple embodiment of the present invention, oscillator 32
`then into a baseband signal. Radio 10 includes an an-
`generates an oscillation signal exhibiting frequencies
`tenna 12, which provides a first RF signal and an op
`generates an oscillation signal exhibiting frequencies
`tenna 12, which provides a first RF signal and an op-
`around 240 MHz. Oscillator 32 couples to an input of an
`tional antenna 14 which provides a second RF signal. In
`around 240 MHz. Oscillator 32 couples to an input of an
`tional antenna 14 which provides a second RF signal. In
`impulse generator 34. Impulse generator 34 generates a
`the preferred embodiment, these RF signals exhibit
`impulse generator 34. Impulse generator 34 generates a
`the preferred embodiment, these RF signals exhibit
`pulse having a width (t) that is less than the period (Tf)
`frequencies in excess of 300 MHz, and quite possibly in
`pulse having a width (7) that is less than the period (To)
`10
`frequencies in excess of 300 MHz, and quite possibly in 10
`of the highest RF signal presented to the sample input of
`excess of 1-7 GHz. The present invention may be
`of the highest RF signal presented to the sample input of
`excess of 1-7 GHz. The present invention may be
`sample and hold circuit 26. A stream of sampling pulses
`adapted to operate at lower frequencies, but the numer
`sample and hold circuit 26. A stream of sampling pulses
`adapted to operate at lower frequencies, but the numer-
`ous advantages of the present invention are pronounced
`at a pulse rate off results. Those skilled in the art will
`at a pulse rate of fs results. Those skilled in the art will
`ous advantages of the present invention are pronounced
`appreciate that impulse generator 34 may be imple
`at higher RF frequencies.
`appreciate that impulse generator 34 may be imple-
`at higher RF frequencies.
`mented using many different techniques. For example,
`An example embodiment is described herein in which
`mented using many different techniques. For example,
`An example embodiment is described herein in which 15
`15
`step recovery diodes and inductor-capacitor (LC) tank
`the first RF signal exhibits a frequency around 7.49
`step recovery diodes and inductor-capacitor (LC) tank
`the first RF signal exhibits a frequency around 7.49
`circuits may be used, or digital flip-flop circuits with
`GHz and the second RF signal exhibits a frequency
`circuits may be used, or digital flip-flop circuits with
`GHz and the second RF signal exhibits a frequency
`feedback may be used (not shown).
`around 2.21 GHz. Radio 10 downconverts both of these
`feedback may be used (not shown).
`around 2.21 GHz. Radio 10 downconverts both of these
`RF signals to an IF signal that exhibits a frequency
`The duration between successive sampling pulses is
`The duration between successive sampling pulses is
`RF signals to an IF signal that exhibits a frequency
`Ts, which equals 1/f, and is approximately 4.167 nano
`around 50 MHz. However, those skilled in the art will
`20
`around 50 MHz. However, those skilled in the art will 2 0 Ts, which equals 1/fs and is approximately 4.167 nano-
`
`appreciate that this example embodiment is presented to
`seconds seconds (ns) in the example embodiment. The
`seconds seconds (ns) in the example embodiment. The
`appreciate that this example embodiment is presented to
`duration T of the sampling pulse is not a critical parame
`illustrate and clarify the concepts embodied by the pres
`duration T of the sampling pulse is not a critical parame-
`illustrate and clarify the concepts embodied by the pres-
`ter in the present invention so long as it remains signifi
`ent invention and that the present invention is in no way
`ent invention and that the present invention is in no way
`ter in the present invention so long as it remains signifi-
`cantly less than the period of the RF signals being sam
`limited to this example embodiment.
`cantly less than the period of the RF signals being sam-
`limited to this example embodiment.
`pled, but is preferably as brief as is reasonably practical.
`Antenna 12 couples to an input of a low noise ampli
`25
`
`Antenna 12 couples to an input of a low noise ampli- 2 5 pled, but is preferably as brief as is reasonably practical.
`fier 16, and an output of amplifier 16 couples to an input
`Moreover, the rise and fall times of the sampling pulse
`fier 16, and an output of amplifier 16 couples to an input
`Moreover, the rise and fall times of the sampling pulse
`are not critical parameters, but are preferably as brief as
`of an image filter 18. Antenna 14 couples to an input of
`of an image filter 18. Antenna 14 couples to an input of
`are not critical parameters, but are preferably as brief as
`is reasonably practical.
`a low noise amplifier 20, and an output of amplifier 20
`a low noise amplifier 20, and an output of amplifier 20
`is reasonably practical.
`Sample and hold circuit 26 operates as a downcon
`couples to an input of an image filter 22. Of course,
`couples to an input of an image filter 22. Of course,
`Sample and hold circuit 26 operates as a downcon-
`verter in radio 10. Sample and hold circuit 26 converts
`those skilled in the art will appreciate that an alternate
`30
`
`those skilled in the art will appreciate that an alternate 3 0 verter in radio 10. Sample and hold circuit 26 converts
`a high frequency RF signal into an IF signal in a single
`embodiment may be constructed in which a single an
`embodiment may be constructed in which a single an-
`a high frequency RF signal into an IF signal in a single
`tenna and RF amplifier drive separate image filters (not
`operation. Moreover, no local oscillator signal at a fre
`tenna and RF amplifier drive separate image filters (not
`operation. Moreover, no local oscillator signal at a fre-
`quency near the RF is generated. Rather, local oscilla
`shown). As is conventional, image filters 18 and 22 are
`shown). As is conventional, image filters 18 and 22 are
`quency near the RF is generated. Rather, local oscilla-
`preferably configured as bandpass filters having center
`tor signals may remain at frequencies less than 3, and
`preferably configured as bandpass filters having center
`tor signals may remain at frequencies less than
`and
`frequencies near the their respective RF frequencies
`preferably significantly less than , of the RF. By re
`35
`
`frequencies near the their respective RF frequencies 3 5 preferably significantly less than
`of the RF. By re-
`fraining from generating local oscillator signals at fre
`and a bandwidths approximately twice the IF fre
`and a bandwidths approximately twice the IF fre-
`fraining from generating local oscillator signals at fre-
`quencies near the RF signal, power consumption and
`quency. For the example embodiment, filter 18 has a
`quency. For the example embodiment, filter 18 has a
`quencies near the RF signal, power consumption and
`circuit volu