CA1175922A - Arrangement for angle modulating a phase-locked loop frequency synthesizer - Google Patents
Arrangement for angle modulating a phase-locked loop frequency synthesizerInfo
- Publication number
- CA1175922A CA1175922A CA000376670A CA376670A CA1175922A CA 1175922 A CA1175922 A CA 1175922A CA 000376670 A CA000376670 A CA 000376670A CA 376670 A CA376670 A CA 376670A CA 1175922 A CA1175922 A CA 1175922A
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- 230000008878 coupling Effects 0.000 claims description 16
- 238000010168 coupling process Methods 0.000 claims description 16
- 238000005859 coupling reaction Methods 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 7
- 230000004044 response Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- NLZUEZXRPGMBCV-UHFFFAOYSA-N Butylhydroxytoluene Chemical compound CC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 NLZUEZXRPGMBCV-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
- H03C3/02—Details
- H03C3/09—Modifications of modulator for regulating the mean frequency
- H03C3/0908—Modifications of modulator for regulating the mean frequency using a phase locked loop
- H03C3/0983—Modifications of modulator for regulating the mean frequency using a phase locked loop containing in the loop a mixer other than for phase detection
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
- H03C3/02—Details
- H03C3/09—Modifications of modulator for regulating the mean frequency
- H03C3/0908—Modifications of modulator for regulating the mean frequency using a phase locked loop
- H03C3/0916—Modifications of modulator for regulating the mean frequency using a phase locked loop with frequency divider or counter in the loop
- H03C3/0925—Modifications of modulator for regulating the mean frequency using a phase locked loop with frequency divider or counter in the loop applying frequency modulation at the divider in the feedback loop
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
- H03C3/02—Details
- H03C3/09—Modifications of modulator for regulating the mean frequency
- H03C3/0908—Modifications of modulator for regulating the mean frequency using a phase locked loop
- H03C3/0941—Modifications of modulator for regulating the mean frequency using a phase locked loop applying frequency modulation at more than one point in the loop
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
- H03C3/02—Details
- H03C3/09—Modifications of modulator for regulating the mean frequency
- H03C3/0908—Modifications of modulator for regulating the mean frequency using a phase locked loop
- H03C3/0958—Modifications of modulator for regulating the mean frequency using a phase locked loop applying frequency modulation by varying the characteristics of the voltage controlled oscillator
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
- H03L7/16—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop
- H03L7/18—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using a frequency divider or counter in the loop
- H03L7/183—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using a frequency divider or counter in the loop a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number
- H03L7/185—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using a frequency divider or counter in the loop a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number using a mixer in the loop
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C2200/00—Indexing scheme relating to details of modulators or modulation methods covered by H03C
- H03C2200/0037—Functional aspects of modulators
- H03C2200/005—Modulation sensitivity
- H03C2200/0054—Filtering of the input modulating signal for obtaining a constant sensitivity of frequency modulation
Landscapes
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
- Transmitters (AREA)
Abstract
ARRANGEMENT FOR ANGLE MODULATING A PHASE-LOCKED LOOP FREQUENCY SYNTHESIZER
ABSTRACT OF THE DISCLOSURE
Various arrangements for eliminating undesired side effects of modulation deviation within a phase-locked loop frequency synthesizer are presented.
Angle modulation is simultaneously applied to two or more points within the synthesizer in order to eliminate the modulation distortion and side band power during modulation otherwise presented in the phase locked loop. In the preferred embodiment, modulation phase shifts which would otherwise be coupled to one of the signal inputs of the loop phase detector are cancelled before they reach the loop phase detector. Modulation is applied simultaneously to the loop voltage controlled oscillator (30) and a converting oscillator (52). The output signal of converting oscillator (52) is mixed with the output signal of voltage controlled oscillator (30) by a mixer (54) to cancel modulation deviation before the loop signal is coupled to divider (36) and to loop phase detector (24).
ABSTRACT OF THE DISCLOSURE
Various arrangements for eliminating undesired side effects of modulation deviation within a phase-locked loop frequency synthesizer are presented.
Angle modulation is simultaneously applied to two or more points within the synthesizer in order to eliminate the modulation distortion and side band power during modulation otherwise presented in the phase locked loop. In the preferred embodiment, modulation phase shifts which would otherwise be coupled to one of the signal inputs of the loop phase detector are cancelled before they reach the loop phase detector. Modulation is applied simultaneously to the loop voltage controlled oscillator (30) and a converting oscillator (52). The output signal of converting oscillator (52) is mixed with the output signal of voltage controlled oscillator (30) by a mixer (54) to cancel modulation deviation before the loop signal is coupled to divider (36) and to loop phase detector (24).
Description
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, ,;, - l - 45 MR 229 ~, ' .", ARRANGEMENT FOR ANGLE MODULATING A PEIASE-.,:, ., , , _, , ~''r LOCKED LOOP FREQUENCY SYNTHESIZER
DESCR PTION
'~; This invention relates generally to phase-locked loop fre-~!, .
, quency synthesizers. Specifically, this invention relates to arrange-' ments for angle modulating phase-locked loop synthesizers. More speci-'~ 5 fically, this invention relates to i~prove arrangements for eliminatingfrom within the phase-locked loop the effects of modulation deviation '~ resulting from the angle modulation of its voltage controlled oscillator.
The prior art and the present invention will be discussed " with reference to the accompanying drawings, in which:
FIGURE l is a block diagram of a conventional phase-l locked loop frequency synthesizer;
.;~; FIGURE 2 is a block diagram of a phase-locked loop frequency synthesizer according to the present invention; and FIGURE 3is ablockdiagram ofan alternate arrangement for the phase-locked loop frequencysynthesizer according to the present invention.
' Frequency synthesizers provide the capability of generatingsignals having a frequency that is selectable over an extensive range while maintaining a high degree o~ frequency stabil:ity when operating at the selacted frequency. rrypiaal frequency syrthesiæers are built ; 20 around a standard phase-locked loop aircuit as set for-th in Chapter 4 o~ FE~EQU~NCY SYNTEIESIZERS THEORY AND DESIGN by Vadim Manassewitsch and published by ~'ohn Wiley & Sons, Inc. 1976.
A conven~ional phase-locked loop ~requency synthe~izer is shown in block cliagram :Ln FIGURE l. Re~erring now to ~I~URE l, a re~erence oscillator 20 provides a signal having a fixed prede-termined frequency FREF. Re~erence oscillator 20 is usually a highly s-table crystal oscillator. The output o~
. - , -, ; .
7~
~ 45 MR 229 .- , ~ reference oscillator 20 is coupled to the input of a .! divider (or multiplier) 2~ having a ratio M. The ~` output of divider 22 is coupled to one of the two . signal inputs A of a loop phase detector 24. The ,; 5 output o phase detector 24 is coupled to the input of a low pass filter ~6. The output of low pass filter ; 26 is coupled to the control input 2~ of a voltage .` controlled oscillator 30. Voltage controlled ;, oscillator 30 includes a high power output 32 for `. 10 coupling to an RF amplifier stage and a low power output 34 for supplying the loop feedback sign2~ for ' coupling to the second input B of loop phase detector .i 24. The low power output 34 of voltage controlled oscillator 30 is coupled to input B of loop phase - 15 detector 24 through a variable ratio divider 36 having a ratio N. Ratio N is controlled by a signal applied to a divide ratio control input 38 of variable ratio divider 36. This signal is usually a multipl e line digital signal responsive to a front panel control o.
an apparatus such as a transceiver into which the fre~uency synthesizer has been incorporated. Thus, the frequenc~ of the high and low power output signals of voltage controlled oscillator 30 is controlled by ratio N as set by tbe user.
Loop phase detector 24 generates an output signal proportional to the phase difference bet~een the signals at its signal inputs A and B. This signal controls the frequency of voltage controlled o.scillator 30 so as to maintain phase lock. In this ~30 manner the frequency F~E~ of reference oscillator 20 ;;and the values o~ M and N determine the fre~uenc~ of the signal appearing at output 32 of voltage controlled oscillator 30. ~ t~pical example oE a :
., . ~ .
.
5 ~ 2~
~ commercially available integrated circuit phase-loc!~ed ; loop frequency synthesizer is the National , Semiconductor MM55124, MM55L26.
.~
For many phase-locked loop frequency i; 5 synthesizer applications, such as in communications equipment, it is advantageous to be able to angle modulate high po~er output 32 of voltage controllec i~ oscillator 30 (also the output of the frequency synthesizer). Angle modulation is usually ; 10 accomplished by coupling a modulating signal to a second control input 40 (also referred to as the modulation input) of voltage controlled oscillator ., 30. - By modulating voltage controlled oscillator 30, modulation deviation appears on the output signal at high power output 32. However, modulation deviatior also appears at low power output 34 of the voltage controlled oscillator and is fed back to input B of loop phase detector 24 through varia~le ratio divider 36. Loop phase detector ~4 sees this deviation as a phase difference between the signals coupled to its A
and B signal inputs and generates a compensating signal at its output. This compensating signal is 2 demodulated replica of the modulating signal applied to input 40 of voltage controlled oscillator 30.
The inherent characteristics of phase detectors such as analog, digital, double-balanced mixers, three-state, etc., cause their output compensating signal to include signal components having the frequency of reference oscillator 20 (as divided or multipled by divider 22) as well as the modulating signal. The amplitude of the reference oscillator fre~uency content presen~ at the output o~
loop phase detector ~4 is proportional to the modulation deviation of the signal at output 34 of voltage controlled oscillator 30. These frequPr.cy components appearing at the outp~t of loop phase detector 24 are undesirable. -. .
In order to eliminate the undesirable S freauency content within the loop, the cut aff , frequency of low pass filter 26 is selected to be .
below the lowest modulation frequency, Thus -modulation deviation products are suppressed within the loop before they are coupled to control input 28 ~
. 10 of volta~e control oscillator 30. The disadvantage associated with relying upon low pass filter 26 for suppression of undesired modulation products within the loop is that the cut off frequency of the filter -must be selected to be so low that the dynamic response of the phase-locked loop is much more ~
~- sluggish than is desirable. The bandwidth of the loop !
must be made smaller than it would have to be made in ~!
the absence of modulation.
Thus, it is desirable to find alternative arrangements for preventing modulation products from ;~
being coupled through the loop to control input 28 of ~-¦
voltage controlled oscillator 30 without the necessity of lowering the cut off frequency of low pass filter 26.
Various arrangements have been utilized for angle modulating phase locked loops in such a manner that the output modulated signal is rendered les~
dependent upon loop transfer characteristics. Or,e such arrangement is set ~orth in U.S. Patent 3,662,gl3 assigned by Don Glen Shipl~y to the RCA Corporation and granted November 23, 1971. In Shipley's ; arrangement, modulation is applied to the VCO and is also applied to a VCXO coupled to one inpu~ of the loop phase detector. In e5sence, Shipley provides a "crossover" network. At low modulating frequencies .. . .
5 45 ~ 229 1 ~ 5~
I ~Y the signal applied to the reference input of the phase ; comparator is a frequency modulated signal that is modulated at the same rate as the output signal. But, ; for higher modulating frequencies, the sig~al applied ~- 5 to the reference input of the phase detector is a constant frequency reference source. ~is arrangement thereby allows the use of ~odulation at low as well as high frequencies~ and is not limitecl by the cut-off point of the loop filter. In another arrangement set forth in U.S. Patent 4,074,209, assigned by Morris Lysobey to the RCA Corporation and granted February 14, 1978, a special modulator is used to bypass the phase-locked loop to inject modulation voltage directly into the voltage controlled oscillator of the loop to broaden the bandwidth of modulation.
However, it is desirable to find less complex and less expensive arrangements for angle modulating phase-locked loop synthesizers over a wide frequency -range while preventing extraneous and undesirable modulation products from being coupled through the loop to control input 28 of voltage controlled oscillator 30 shown in FIGURE 1.
DISC~OSURE OF THE INVENTION
Therefore, the present invention is directed to arrangements for suppressing angle modulation deviation products within a phase-locked loop frequency synthesizer without relying upon a low pass loop filter for attenuating the undesired frequency j componen~s. Utili~iing such alternate arrangements ; 3~ permits the designer of a phase-locked loop ~' synthesi~er to use a higher cut-off frequency for the :; r loop low pass filter thereby enhancing loop bandwidth and dynamic response.
, .
, ~
" .
~ .
, ~,.
,...
: ';
, ,;, - l - 45 MR 229 ~, ' .", ARRANGEMENT FOR ANGLE MODULATING A PEIASE-.,:, ., , , _, , ~''r LOCKED LOOP FREQUENCY SYNTHESIZER
DESCR PTION
'~; This invention relates generally to phase-locked loop fre-~!, .
, quency synthesizers. Specifically, this invention relates to arrange-' ments for angle modulating phase-locked loop synthesizers. More speci-'~ 5 fically, this invention relates to i~prove arrangements for eliminatingfrom within the phase-locked loop the effects of modulation deviation '~ resulting from the angle modulation of its voltage controlled oscillator.
The prior art and the present invention will be discussed " with reference to the accompanying drawings, in which:
FIGURE l is a block diagram of a conventional phase-l locked loop frequency synthesizer;
.;~; FIGURE 2 is a block diagram of a phase-locked loop frequency synthesizer according to the present invention; and FIGURE 3is ablockdiagram ofan alternate arrangement for the phase-locked loop frequencysynthesizer according to the present invention.
' Frequency synthesizers provide the capability of generatingsignals having a frequency that is selectable over an extensive range while maintaining a high degree o~ frequency stabil:ity when operating at the selacted frequency. rrypiaal frequency syrthesiæers are built ; 20 around a standard phase-locked loop aircuit as set for-th in Chapter 4 o~ FE~EQU~NCY SYNTEIESIZERS THEORY AND DESIGN by Vadim Manassewitsch and published by ~'ohn Wiley & Sons, Inc. 1976.
A conven~ional phase-locked loop ~requency synthe~izer is shown in block cliagram :Ln FIGURE l. Re~erring now to ~I~URE l, a re~erence oscillator 20 provides a signal having a fixed prede-termined frequency FREF. Re~erence oscillator 20 is usually a highly s-table crystal oscillator. The output o~
. - , -, ; .
7~
~ 45 MR 229 .- , ~ reference oscillator 20 is coupled to the input of a .! divider (or multiplier) 2~ having a ratio M. The ~` output of divider 22 is coupled to one of the two . signal inputs A of a loop phase detector 24. The ,; 5 output o phase detector 24 is coupled to the input of a low pass filter ~6. The output of low pass filter ; 26 is coupled to the control input 2~ of a voltage .` controlled oscillator 30. Voltage controlled ;, oscillator 30 includes a high power output 32 for `. 10 coupling to an RF amplifier stage and a low power output 34 for supplying the loop feedback sign2~ for ' coupling to the second input B of loop phase detector .i 24. The low power output 34 of voltage controlled oscillator 30 is coupled to input B of loop phase - 15 detector 24 through a variable ratio divider 36 having a ratio N. Ratio N is controlled by a signal applied to a divide ratio control input 38 of variable ratio divider 36. This signal is usually a multipl e line digital signal responsive to a front panel control o.
an apparatus such as a transceiver into which the fre~uency synthesizer has been incorporated. Thus, the frequenc~ of the high and low power output signals of voltage controlled oscillator 30 is controlled by ratio N as set by tbe user.
Loop phase detector 24 generates an output signal proportional to the phase difference bet~een the signals at its signal inputs A and B. This signal controls the frequency of voltage controlled o.scillator 30 so as to maintain phase lock. In this ~30 manner the frequency F~E~ of reference oscillator 20 ;;and the values o~ M and N determine the fre~uenc~ of the signal appearing at output 32 of voltage controlled oscillator 30. ~ t~pical example oE a :
., . ~ .
.
5 ~ 2~
~ commercially available integrated circuit phase-loc!~ed ; loop frequency synthesizer is the National , Semiconductor MM55124, MM55L26.
.~
For many phase-locked loop frequency i; 5 synthesizer applications, such as in communications equipment, it is advantageous to be able to angle modulate high po~er output 32 of voltage controllec i~ oscillator 30 (also the output of the frequency synthesizer). Angle modulation is usually ; 10 accomplished by coupling a modulating signal to a second control input 40 (also referred to as the modulation input) of voltage controlled oscillator ., 30. - By modulating voltage controlled oscillator 30, modulation deviation appears on the output signal at high power output 32. However, modulation deviatior also appears at low power output 34 of the voltage controlled oscillator and is fed back to input B of loop phase detector 24 through varia~le ratio divider 36. Loop phase detector ~4 sees this deviation as a phase difference between the signals coupled to its A
and B signal inputs and generates a compensating signal at its output. This compensating signal is 2 demodulated replica of the modulating signal applied to input 40 of voltage controlled oscillator 30.
The inherent characteristics of phase detectors such as analog, digital, double-balanced mixers, three-state, etc., cause their output compensating signal to include signal components having the frequency of reference oscillator 20 (as divided or multipled by divider 22) as well as the modulating signal. The amplitude of the reference oscillator fre~uency content presen~ at the output o~
loop phase detector ~4 is proportional to the modulation deviation of the signal at output 34 of voltage controlled oscillator 30. These frequPr.cy components appearing at the outp~t of loop phase detector 24 are undesirable. -. .
In order to eliminate the undesirable S freauency content within the loop, the cut aff , frequency of low pass filter 26 is selected to be .
below the lowest modulation frequency, Thus -modulation deviation products are suppressed within the loop before they are coupled to control input 28 ~
. 10 of volta~e control oscillator 30. The disadvantage associated with relying upon low pass filter 26 for suppression of undesired modulation products within the loop is that the cut off frequency of the filter -must be selected to be so low that the dynamic response of the phase-locked loop is much more ~
~- sluggish than is desirable. The bandwidth of the loop !
must be made smaller than it would have to be made in ~!
the absence of modulation.
Thus, it is desirable to find alternative arrangements for preventing modulation products from ;~
being coupled through the loop to control input 28 of ~-¦
voltage controlled oscillator 30 without the necessity of lowering the cut off frequency of low pass filter 26.
Various arrangements have been utilized for angle modulating phase locked loops in such a manner that the output modulated signal is rendered les~
dependent upon loop transfer characteristics. Or,e such arrangement is set ~orth in U.S. Patent 3,662,gl3 assigned by Don Glen Shipl~y to the RCA Corporation and granted November 23, 1971. In Shipley's ; arrangement, modulation is applied to the VCO and is also applied to a VCXO coupled to one inpu~ of the loop phase detector. In e5sence, Shipley provides a "crossover" network. At low modulating frequencies .. . .
5 45 ~ 229 1 ~ 5~
I ~Y the signal applied to the reference input of the phase ; comparator is a frequency modulated signal that is modulated at the same rate as the output signal. But, ; for higher modulating frequencies, the sig~al applied ~- 5 to the reference input of the phase detector is a constant frequency reference source. ~is arrangement thereby allows the use of ~odulation at low as well as high frequencies~ and is not limitecl by the cut-off point of the loop filter. In another arrangement set forth in U.S. Patent 4,074,209, assigned by Morris Lysobey to the RCA Corporation and granted February 14, 1978, a special modulator is used to bypass the phase-locked loop to inject modulation voltage directly into the voltage controlled oscillator of the loop to broaden the bandwidth of modulation.
However, it is desirable to find less complex and less expensive arrangements for angle modulating phase-locked loop synthesizers over a wide frequency -range while preventing extraneous and undesirable modulation products from being coupled through the loop to control input 28 of voltage controlled oscillator 30 shown in FIGURE 1.
DISC~OSURE OF THE INVENTION
Therefore, the present invention is directed to arrangements for suppressing angle modulation deviation products within a phase-locked loop frequency synthesizer without relying upon a low pass loop filter for attenuating the undesired frequency j componen~s. Utili~iing such alternate arrangements ; 3~ permits the designer of a phase-locked loop ~' synthesi~er to use a higher cut-off frequency for the :; r loop low pass filter thereby enhancing loop bandwidth and dynamic response.
, .
, ~
2 ~ ~5 M~
Two different circuit arrangements are presented wherein modulation is applied simultaneously to two points within a phase-locked loop synthesizer so as to cancel or compensate for phase diferences between the signals at inputs A and B of loop phase detector 24 resulting from the angle modulation of its - voltage controlled oscillator.
Thus, there is provided an arran~ement or suppressing undesirable frequency components in an `~' angle mod~lated phase-locked loop freq~ency synthesizer comprising means for applying a common modulating signal simultaneously to two different elements of the phase-locked loop in order to maintain - the phase ratio of the signals developed at the phase lS detector input ports constant.
;~ In the preferred embodiment, ~ , a converting oscillator is modulated with the same modulating signal applied to input 40 of voltage controlled oscillator 30. Out~ut signals of voltage controlled oscillator 30 and the converting oscillator are mi~ed to cancel modulation deviation. The output of the mixer is coupled through variable ratio divider 36 to the B signal input of loop phase detector 24.
In essence, there is provided a phase-locked loop circuit comprising:
; - a reference oscillator for providing a reference signal having a fixed predetermined frequency;
- a loop phase detector having a ~irst input coupled to the output of said reference oscillator, a second input and an output for providing a signal related to the phase difference between the signals coupled to its ~irst and second inputs;
i . :
....................................................................... I
,. . .
~ - a low pass filter having an input couplecd - to the output of said loop phase detector and having . an output;
: - a voltage controlled oscillator having a : 5 first control input for controlling the operating frequency thereo coupled to the ou~put o~ said low pass filter, a second control input for coupling to a : modulating signal and an output;
- a converting oscillator having a first L' 10 input for coupling to the modulating signal and an output for providing a signal having the same deviation as the deviation of the output siqnal of said voltage controlled oscillator resulting from the modulating signal;
- a mixer having a first signal input coupled ~ to the output of said voltage controlled oscillator, a :~ _ second si~;nal ~nput coupled tot:he output of the converting oscillator and an output for providing a difference signal free of mod~lation deviation; and - a variable divider having a ratio control input for receiving a ratio control signal, a signal input coupled to the output of said mi~er, and a ~ signal output coupled to the second input o~ said loop ; phase detector.
.. 25 In a second arrangement,FIG- 3, a ~trol signal isgenerated that is responsive to the modulating signal ; applied to input 40 of voltage controlled oscillator ; 30. This control signal is used to control an i incremental change of the ratio N o~ variabLe ratio divider so as to eliminate any modulation deviation ~rom its output.
In this seconcl arrangemen~, there is provided a phase-locked loop circuit comprislng:
;, - a ~eference oscillator for providins a reference signal having a fixed predetermined frequency;
- a loop phase detector having a f irst input coupled to output of said reference oscillator, a second input, and an output for providing a signal related to the phase difference between the signals at said first and second inputs;
- a low pass filter coupled to the output of said loop phase detector;
- a voltage controlled oscillator having its . control input coupled to the output of said low pass :~ filter, a second control input for coupling to a . modulating ~ignal and an output;
: 15 - a variable ratio divider having a signal input for coupling to the output of said voltage controlled oscillator, a signal output and a control input for incrementallY controlling its ratio; and - means for generating a signal related to r the modulation deviation of said voltage controlled oscillator coupled to the control input of said variable ratio divider for causing an incremental ~hange of the ratio of said variable ratio divider thereby adjusting the phase of the signal at said second input of said loop phase detector such that said loop phase detector sees no phase difference between its first and second inputs due to the modulating signal.
Thus, there is defined a method for eliminat1ng the effects of modulation deviation within an angle modu].ated phase-locked loop ~requency synthesizer comprising the steps of:
r anyle modulating the voltage control oscillator with a modulating signal;
~ 6~
~ ~ ~ ~ 45 M~ ~9 .,. 9 ' ~ _ ~ angle mdoulating a con~ertins oscillator sc that the output of the converting oscillator has the same modualtion deviation as ~he output of the voltase controlled oscillator;
S ~ mixing the output of the vo'.age controlled oscillator and the converting oscillator so ~s to eliminate all modulation deviation resulting from the modulating signal; and ~ coupling the output of the mixer to a 10 signal input of the phase detector of the phase--lockec `~ loop.
There is also defined a method for eliminating the modulation deviation from an angle E
modulated phase-locked loop frequency syntnesizer of the type including a reference oscillator, a loop phase detector having a first input coupled to the output of the reference oscillator, a low p2SS filter coupling the output of the loop phase detector to a ~ voltage control oscillator, and a variable ratio ,~ 20 divider coupling the output of the voltage cont~ol oscillator to a second input of the phase detector comprising the steps of:
- angle modulating the voltage control oscillator with a modulating signal; and - varying the ratio of the variable ratio divider so as to eliminate phase shifts in the signal coupled to the second input of the 1Oo2 phase detector resultins ~rom deviation in the outpllt of the voltage controlled oscillator.
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.
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.- - 10 - 45 MR 229 ' Referring to the drawings wherein like reference numerals designate like or corresponding parts throughout the several views, and specifically referring to FI~URE 2, there is shown a block diagram of the presently preferred exemplary embodiment of the arrangement according to the present invention for eliminating the undesirable effects of modulation within a phase-locked loop frequency synthesizer.
The conventional synthesizer arrangement shown in FIGURE 1 is modified by the addition of a level control 50, a converting oscillator 52, and a mixer 54. The modulating signal which is coupled .. to input 40 of voltage controlled oscillator 30 is also coupled through level control 50 to a converting oscillator 52. Level control 50, suitably a variable attenuator or variable gain ampli~ier is adjusted such that .
11 ~5 ~ q ,~ , converting oscilla~or S2 is modulated to produce an output signal deviation identica~ to the deviation of the ~i~nal at output 34 of voltage controlled .
oscillator 30. The outp~t of converting oscillator 52 is coupled to one input of mixer 54. The other inpu~
of mixer S4 is coupled to output 34 of voltage controlled oscillator 30. The output of mixer 5d is coupled to the i~put of variable ratio divi~er 36, suitably a programmable divider.
The purpose of mixer 54 is to ~cancel" the modulation deviation effects of the modulating signal. The output 34 of voltage controlled oscillator 30 includes a deviation resulting from the t modulating signal applied to input 40 thereof.
;~' 15 Converting oscillator 52 is modulated so as to produce ~ identical deviation and thus identical phase shift to : ~ the deviation of voltage controlled oscillator 3U.
Thus, the output of mixer 54 representing the . difference between its two inputs, does not include any deviation resulting from modulating signal. Level control 50 is utilized to set the level of modulati~g signal coupled to the input of converting oscillator 52 so that the deviation of the output signal of the con~erting oscillator will be identical to the .: 25 deviation at output 34 of voltage control oscillator 30. Typically, converting oscillator 52 operates at a different output fre~uency than the frequency of the voltage controlled oscillator 30. Mixer 54 provides at its output the difference between the fre~uencies , 30 of signals at its two inputs. Of course, the .. fre~uencies of reference oscillator 20, converting oscillator 52, and the divide ratios of divider 22 and the range of ratio of variable ratio divider 3S are selected to be compatible with the desired loop : 35 response and output frequency range.
45 MR ~29 : ,,.~ ~
,.;~ li Utilizing this circuit arrangement, ~o deviation resulting from the modulating signal appears ~-at the output of mixer 54 and thus there is no need to filter these deviation products at low pass filter 26.- Therefore, the cut off freq~ency of low pass filter 26 can be moved to a higher frequency, giving faster loop response a~d wider bandwid~h.
There is an alternate arrangements set forth below for accompllshing this "cancellation" effect.
It is intended that the scope of this invention not be limited to the presently preferred e:~emplary embodiment shown in FIGURE 2 or in the alternate embodiment set forth thereafter, but rather that the scope of invention include further alternat~
arrangements within the spirit of the arransements set ` ~ forth herein and suggested thereby to one of ordinary skill in the art.
Referring now to FIGURE 3 there is shown an alternate arrangement for cancelling the modulation 2a deviation withln the loop of a phase-locked loop frequency synthesizer. In this particular embodiment, the variable ratio divider 36 shown in FIGURE 2 now includes a second control input 62. Variable ratio divider 36 is capable of incrementallv changing its divide ratio in response to a signal coupled to this second control input 62. The modulating signal ; applied to input 40 o~ voltage controlled oscillator 30 is also coupled to the input of an analos to digital converter 64. Analog to digital converter 64 generates a signal at its output 66 related to ~he deviation of voltage controlled oscillator 30 induced ~; by the modulating signalO A variable attenuator or variable gain amplifier can be used to couple to the mvdulating signal to analog to digital converter 64 so that its output level can be controlled.
~' ~,',, ~' .
, 13 ~5 MR 22g It is contemplated that control input 62 o~ ¦
variable ra~io divider 36 is digital and thus an analog to digi~al converter 64 is utili~ed to generate a digital sisnal at its outpu~ 66 related to modulation deviation. However, ~or use in a synthesizer having a variable ratio divider 36 with ., ' analog control, suitable modification can be made such that an analog signal coupled to contro.l input 62 ,`,. would alter the divide ratio incrementally. Output 34 '~. lO of voltage control oscillator 30 is coupled to the signal input of variable ratio di~ider 36 and is operated upon in accordance with the divide ratio.of :. the variable ratio divider. The output of variable ratio divider 36 is coupled to the B input of loop .
phase detector 24.
There is a nominal value of N for a locked condition of the phase-lock loop based upon the ~requencies of reference oscillator 20, voltage controlled oscillator 30 and the divide ratios of dividers 22 and 36. If analog to digital converter 64 and its associated input and output were disconnected, modulation applied to input 40 of voltage control oscillator would cause a modulation deviation to occur at its output 34 which would be divided by varia~le ! 25 ratio divider 36 and coupled to the B input of loop phase detector 24. ~owever,~by utilizing a control signal generated by analog to digital converter 64, ~he ratio of variable ratio divider 36 is incrementally adjusted so that the output of the divider coupled to the 8 input o~ phase detector 24 is ~re~ o~ deviations resulting from modulating signal.
In other words, the nominal value o~ N for a stable locked condition in the absence of modul,ating signal is altered incrementally as modulation is appLied. In this manner, the divide ratio of variable ratio 1 l 7~ 45 MR 229 ,'~ i divider 36 varies with the modulating signal, constantly adjusting the phase of the signal at its output coupled to the B input of loop phase detector 24. This phase adjustment is specifically designed to cancel out phase changes resulting from the modulation deviation appearing at output 34 of voltage control oscillator 30.
The two arrangements shown in FIGU2ES 2 and 3 relate to schemes for cancelling or eliminating the effect of modulation deviation within a phase-locked loop frequency synthesizer that is angle modulated.
Other embodiments and modifications of the present invention will be apparent to those of ordinary skill in the art having the benefit of the teachings presented in the foregoing description and ;~ ~ drawings. It is therefore to be understood that this invention is not to be unduly limited and such modifications are intended to be included within the scope of the appended claims.
, 20 INDUSTRIAL APPLICABILITY
, The phase-locked loop frequency synthesizer arrangements presented herein are particularly ~seful for co~unications equipment applications wherein modulation must be applied to a synthesized signal.
By using these arrangements, a designer of such equipment is given a greater degree of freedom in selectlng the cut-of ~requency of the loop filter o~
the phase-locked loop to achieve a desired bandwidth and dyna~ic response. These arrangements also have two important improvements useful for communication r equipment, tha~. is, low modulation distortion near loop cxoss over and low adjacent channel side band power.
.....
., :.~
:
.. ..
~,,'' ., ~.
.:
.,
Two different circuit arrangements are presented wherein modulation is applied simultaneously to two points within a phase-locked loop synthesizer so as to cancel or compensate for phase diferences between the signals at inputs A and B of loop phase detector 24 resulting from the angle modulation of its - voltage controlled oscillator.
Thus, there is provided an arran~ement or suppressing undesirable frequency components in an `~' angle mod~lated phase-locked loop freq~ency synthesizer comprising means for applying a common modulating signal simultaneously to two different elements of the phase-locked loop in order to maintain - the phase ratio of the signals developed at the phase lS detector input ports constant.
;~ In the preferred embodiment, ~ , a converting oscillator is modulated with the same modulating signal applied to input 40 of voltage controlled oscillator 30. Out~ut signals of voltage controlled oscillator 30 and the converting oscillator are mi~ed to cancel modulation deviation. The output of the mixer is coupled through variable ratio divider 36 to the B signal input of loop phase detector 24.
In essence, there is provided a phase-locked loop circuit comprising:
; - a reference oscillator for providing a reference signal having a fixed predetermined frequency;
- a loop phase detector having a ~irst input coupled to the output of said reference oscillator, a second input and an output for providing a signal related to the phase difference between the signals coupled to its ~irst and second inputs;
i . :
....................................................................... I
,. . .
~ - a low pass filter having an input couplecd - to the output of said loop phase detector and having . an output;
: - a voltage controlled oscillator having a : 5 first control input for controlling the operating frequency thereo coupled to the ou~put o~ said low pass filter, a second control input for coupling to a : modulating signal and an output;
- a converting oscillator having a first L' 10 input for coupling to the modulating signal and an output for providing a signal having the same deviation as the deviation of the output siqnal of said voltage controlled oscillator resulting from the modulating signal;
- a mixer having a first signal input coupled ~ to the output of said voltage controlled oscillator, a :~ _ second si~;nal ~nput coupled tot:he output of the converting oscillator and an output for providing a difference signal free of mod~lation deviation; and - a variable divider having a ratio control input for receiving a ratio control signal, a signal input coupled to the output of said mi~er, and a ~ signal output coupled to the second input o~ said loop ; phase detector.
.. 25 In a second arrangement,FIG- 3, a ~trol signal isgenerated that is responsive to the modulating signal ; applied to input 40 of voltage controlled oscillator ; 30. This control signal is used to control an i incremental change of the ratio N o~ variabLe ratio divider so as to eliminate any modulation deviation ~rom its output.
In this seconcl arrangemen~, there is provided a phase-locked loop circuit comprislng:
;, - a ~eference oscillator for providins a reference signal having a fixed predetermined frequency;
- a loop phase detector having a f irst input coupled to output of said reference oscillator, a second input, and an output for providing a signal related to the phase difference between the signals at said first and second inputs;
- a low pass filter coupled to the output of said loop phase detector;
- a voltage controlled oscillator having its . control input coupled to the output of said low pass :~ filter, a second control input for coupling to a . modulating ~ignal and an output;
: 15 - a variable ratio divider having a signal input for coupling to the output of said voltage controlled oscillator, a signal output and a control input for incrementallY controlling its ratio; and - means for generating a signal related to r the modulation deviation of said voltage controlled oscillator coupled to the control input of said variable ratio divider for causing an incremental ~hange of the ratio of said variable ratio divider thereby adjusting the phase of the signal at said second input of said loop phase detector such that said loop phase detector sees no phase difference between its first and second inputs due to the modulating signal.
Thus, there is defined a method for eliminat1ng the effects of modulation deviation within an angle modu].ated phase-locked loop ~requency synthesizer comprising the steps of:
r anyle modulating the voltage control oscillator with a modulating signal;
~ 6~
~ ~ ~ ~ 45 M~ ~9 .,. 9 ' ~ _ ~ angle mdoulating a con~ertins oscillator sc that the output of the converting oscillator has the same modualtion deviation as ~he output of the voltase controlled oscillator;
S ~ mixing the output of the vo'.age controlled oscillator and the converting oscillator so ~s to eliminate all modulation deviation resulting from the modulating signal; and ~ coupling the output of the mixer to a 10 signal input of the phase detector of the phase--lockec `~ loop.
There is also defined a method for eliminating the modulation deviation from an angle E
modulated phase-locked loop frequency syntnesizer of the type including a reference oscillator, a loop phase detector having a first input coupled to the output of the reference oscillator, a low p2SS filter coupling the output of the loop phase detector to a ~ voltage control oscillator, and a variable ratio ,~ 20 divider coupling the output of the voltage cont~ol oscillator to a second input of the phase detector comprising the steps of:
- angle modulating the voltage control oscillator with a modulating signal; and - varying the ratio of the variable ratio divider so as to eliminate phase shifts in the signal coupled to the second input of the 1Oo2 phase detector resultins ~rom deviation in the outpllt of the voltage controlled oscillator.
. .
r V
. ~ . .
.
'7S92~:
.- - 10 - 45 MR 229 ' Referring to the drawings wherein like reference numerals designate like or corresponding parts throughout the several views, and specifically referring to FI~URE 2, there is shown a block diagram of the presently preferred exemplary embodiment of the arrangement according to the present invention for eliminating the undesirable effects of modulation within a phase-locked loop frequency synthesizer.
The conventional synthesizer arrangement shown in FIGURE 1 is modified by the addition of a level control 50, a converting oscillator 52, and a mixer 54. The modulating signal which is coupled .. to input 40 of voltage controlled oscillator 30 is also coupled through level control 50 to a converting oscillator 52. Level control 50, suitably a variable attenuator or variable gain ampli~ier is adjusted such that .
11 ~5 ~ q ,~ , converting oscilla~or S2 is modulated to produce an output signal deviation identica~ to the deviation of the ~i~nal at output 34 of voltage controlled .
oscillator 30. The outp~t of converting oscillator 52 is coupled to one input of mixer 54. The other inpu~
of mixer S4 is coupled to output 34 of voltage controlled oscillator 30. The output of mixer 5d is coupled to the i~put of variable ratio divi~er 36, suitably a programmable divider.
The purpose of mixer 54 is to ~cancel" the modulation deviation effects of the modulating signal. The output 34 of voltage controlled oscillator 30 includes a deviation resulting from the t modulating signal applied to input 40 thereof.
;~' 15 Converting oscillator 52 is modulated so as to produce ~ identical deviation and thus identical phase shift to : ~ the deviation of voltage controlled oscillator 3U.
Thus, the output of mixer 54 representing the . difference between its two inputs, does not include any deviation resulting from modulating signal. Level control 50 is utilized to set the level of modulati~g signal coupled to the input of converting oscillator 52 so that the deviation of the output signal of the con~erting oscillator will be identical to the .: 25 deviation at output 34 of voltage control oscillator 30. Typically, converting oscillator 52 operates at a different output fre~uency than the frequency of the voltage controlled oscillator 30. Mixer 54 provides at its output the difference between the fre~uencies , 30 of signals at its two inputs. Of course, the .. fre~uencies of reference oscillator 20, converting oscillator 52, and the divide ratios of divider 22 and the range of ratio of variable ratio divider 3S are selected to be compatible with the desired loop : 35 response and output frequency range.
45 MR ~29 : ,,.~ ~
,.;~ li Utilizing this circuit arrangement, ~o deviation resulting from the modulating signal appears ~-at the output of mixer 54 and thus there is no need to filter these deviation products at low pass filter 26.- Therefore, the cut off freq~ency of low pass filter 26 can be moved to a higher frequency, giving faster loop response a~d wider bandwid~h.
There is an alternate arrangements set forth below for accompllshing this "cancellation" effect.
It is intended that the scope of this invention not be limited to the presently preferred e:~emplary embodiment shown in FIGURE 2 or in the alternate embodiment set forth thereafter, but rather that the scope of invention include further alternat~
arrangements within the spirit of the arransements set ` ~ forth herein and suggested thereby to one of ordinary skill in the art.
Referring now to FIGURE 3 there is shown an alternate arrangement for cancelling the modulation 2a deviation withln the loop of a phase-locked loop frequency synthesizer. In this particular embodiment, the variable ratio divider 36 shown in FIGURE 2 now includes a second control input 62. Variable ratio divider 36 is capable of incrementallv changing its divide ratio in response to a signal coupled to this second control input 62. The modulating signal ; applied to input 40 o~ voltage controlled oscillator 30 is also coupled to the input of an analos to digital converter 64. Analog to digital converter 64 generates a signal at its output 66 related to ~he deviation of voltage controlled oscillator 30 induced ~; by the modulating signalO A variable attenuator or variable gain amplifier can be used to couple to the mvdulating signal to analog to digital converter 64 so that its output level can be controlled.
~' ~,',, ~' .
, 13 ~5 MR 22g It is contemplated that control input 62 o~ ¦
variable ra~io divider 36 is digital and thus an analog to digi~al converter 64 is utili~ed to generate a digital sisnal at its outpu~ 66 related to modulation deviation. However, ~or use in a synthesizer having a variable ratio divider 36 with ., ' analog control, suitable modification can be made such that an analog signal coupled to contro.l input 62 ,`,. would alter the divide ratio incrementally. Output 34 '~. lO of voltage control oscillator 30 is coupled to the signal input of variable ratio di~ider 36 and is operated upon in accordance with the divide ratio.of :. the variable ratio divider. The output of variable ratio divider 36 is coupled to the B input of loop .
phase detector 24.
There is a nominal value of N for a locked condition of the phase-lock loop based upon the ~requencies of reference oscillator 20, voltage controlled oscillator 30 and the divide ratios of dividers 22 and 36. If analog to digital converter 64 and its associated input and output were disconnected, modulation applied to input 40 of voltage control oscillator would cause a modulation deviation to occur at its output 34 which would be divided by varia~le ! 25 ratio divider 36 and coupled to the B input of loop phase detector 24. ~owever,~by utilizing a control signal generated by analog to digital converter 64, ~he ratio of variable ratio divider 36 is incrementally adjusted so that the output of the divider coupled to the 8 input o~ phase detector 24 is ~re~ o~ deviations resulting from modulating signal.
In other words, the nominal value o~ N for a stable locked condition in the absence of modul,ating signal is altered incrementally as modulation is appLied. In this manner, the divide ratio of variable ratio 1 l 7~ 45 MR 229 ,'~ i divider 36 varies with the modulating signal, constantly adjusting the phase of the signal at its output coupled to the B input of loop phase detector 24. This phase adjustment is specifically designed to cancel out phase changes resulting from the modulation deviation appearing at output 34 of voltage control oscillator 30.
The two arrangements shown in FIGU2ES 2 and 3 relate to schemes for cancelling or eliminating the effect of modulation deviation within a phase-locked loop frequency synthesizer that is angle modulated.
Other embodiments and modifications of the present invention will be apparent to those of ordinary skill in the art having the benefit of the teachings presented in the foregoing description and ;~ ~ drawings. It is therefore to be understood that this invention is not to be unduly limited and such modifications are intended to be included within the scope of the appended claims.
, 20 INDUSTRIAL APPLICABILITY
, The phase-locked loop frequency synthesizer arrangements presented herein are particularly ~seful for co~unications equipment applications wherein modulation must be applied to a synthesized signal.
By using these arrangements, a designer of such equipment is given a greater degree of freedom in selectlng the cut-of ~requency of the loop filter o~
the phase-locked loop to achieve a desired bandwidth and dyna~ic response. These arrangements also have two important improvements useful for communication r equipment, tha~. is, low modulation distortion near loop cxoss over and low adjacent channel side band power.
.....
., :.~
:
.. ..
~,,'' ., ~.
.:
.,
Claims (7)
1. A phase-locked loop circuit comprising:
a reference oscillator for providing a reference signal having a fixed predetermined frequency;
a loop phase detector having a first input coupled to output of said reference oscillator, a second input, and an output for providing a signal related to the phase difference between the signals at said first and second inputs;
a low pass filter coupled to the output of said loop phase detector;
a voltage controlled oscillator having its control input coupled to the output of said low pass filter, a second control input for coupling to a modulating signal and an output;
a variable ratio divider having a signal input for coupling to the input of said voltage controlled oscillator, a signal output and a control input for incrementally controlling its ratio; and means for generating a signal related to the modulation deviation of said voltage controlled oscillator coupled to the control input of said variable ratio divider for causing an incremental change of the ratio of said variable ratio divider thereby adjusting the phase of the signal at said second input of said loop phase detector such that said loop phase detector sees no phase difference between its first and second inputs due to the modulating signal.
a reference oscillator for providing a reference signal having a fixed predetermined frequency;
a loop phase detector having a first input coupled to output of said reference oscillator, a second input, and an output for providing a signal related to the phase difference between the signals at said first and second inputs;
a low pass filter coupled to the output of said loop phase detector;
a voltage controlled oscillator having its control input coupled to the output of said low pass filter, a second control input for coupling to a modulating signal and an output;
a variable ratio divider having a signal input for coupling to the input of said voltage controlled oscillator, a signal output and a control input for incrementally controlling its ratio; and means for generating a signal related to the modulation deviation of said voltage controlled oscillator coupled to the control input of said variable ratio divider for causing an incremental change of the ratio of said variable ratio divider thereby adjusting the phase of the signal at said second input of said loop phase detector such that said loop phase detector sees no phase difference between its first and second inputs due to the modulating signal.
2. A phase-locked loop circuit according to claim 1 wherein said means for generating a signal is an analog to digital converter.
3. A phase locked loop circuit according to either of claim 1 or 2 further including a divider coupling said reference oscillator to the first input of said loop phase detector.
4. A phase-locked loop circuit according to either of claim 1 or 2 further including a multiplier coupling said reference oscillator to the first input of said loop phase detector.
5. A phase-locked loop circuit according to any of claim 1 or 2 further including an attenuator coupled to the input of said analog to digital converter for controlling the level of modulation coupled to said analog to digital converter.
6. A phase-locked loop circuit according to any of claim 1 or 2 further including a variable gain amplifier coupled to the input of said analog to digital converter for controlling the level of modulation coupled to said analog to digital converter.
7. A method for eliminating the modulation deviation from an angle modulated phase-locked loop frequency synthesizer of the type including a reference oscillator, a loop phase detector having a first input coupled to the output of the reference oscillator, a low pass filter coupling the output of the loop phase detector to a voltage control oscillator, and a variable ratio divider coupling the output of the voltage control oscillator to a second input of the phase detector comprising the steps of:
angle modulating the voltage control oscillator with a modulating signal; and varying the ratio of the variable ratio divider so as to eliminate phase shifts in the signal coupled to the second input of the loop phase detector resulting from deviation in the output of the voltage controlled oscillator.
angle modulating the voltage control oscillator with a modulating signal; and varying the ratio of the variable ratio divider so as to eliminate phase shifts in the signal coupled to the second input of the loop phase detector resulting from deviation in the output of the voltage controlled oscillator.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1980/000501 WO1981003250A1 (en) | 1980-05-01 | 1980-05-01 | Arrangement for angle modulating a phase-locked loop frequency synthesizer |
| US501 | 1980-05-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1175922A true CA1175922A (en) | 1984-10-09 |
Family
ID=22154314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000376670A Expired CA1175922A (en) | 1980-05-01 | 1981-05-01 | Arrangement for angle modulating a phase-locked loop frequency synthesizer |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0050124A4 (en) |
| JP (1) | JPS57500761A (en) |
| CA (1) | CA1175922A (en) |
| DE (1) | DE50124T1 (en) |
| DK (1) | DK578981A (en) |
| WO (1) | WO1981003250A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58105631A (en) * | 1981-12-17 | 1983-06-23 | Nec Corp | Frequency modulating transmitter |
| GB2140234B (en) * | 1983-05-17 | 1986-07-23 | Marconi Instruments Ltd | Signal generators |
| US4755774A (en) * | 1985-07-15 | 1988-07-05 | Motorola Inc. | Two-port synthesizer modulation system employing an improved reference phase modulator |
| DE8712331U1 (en) * | 1986-09-26 | 1988-01-28 | Flowtec AG, Reinach, Basel | Coriolis force mass flow meter |
| DE19601013A1 (en) * | 1996-01-13 | 1997-07-17 | Bosch Gmbh Robert | Method and arrangement for frequency modulation of a high-frequency signal |
| FR2798019B1 (en) * | 1999-08-26 | 2002-08-16 | Cit Alcatel | PHASE LOOP FREQUENCY SYNTHESIZER |
| GB2389252B (en) | 2002-05-31 | 2006-09-27 | Zarlink Semiconductor Ltd | A frequency modulation system & method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3593182A (en) * | 1969-04-16 | 1971-07-13 | Motorola Inc | Afc system for microwave energy sources |
| US3622913A (en) * | 1969-10-29 | 1971-11-23 | Rca Corp | Frequency modulated phase-locked oscillator having a low- and high-frequency response |
| US3805192A (en) * | 1972-08-09 | 1974-04-16 | Electronic Communications | Frequency modulator-variable frequency generator |
| DE2914814A1 (en) * | 1979-04-11 | 1980-10-30 | Siemens Ag | FREQUENCY MODULATOR |
-
1980
- 1980-05-01 DE DE198181900873T patent/DE50124T1/en active Pending
- 1980-05-01 WO PCT/US1980/000501 patent/WO1981003250A1/en not_active Application Discontinuation
- 1980-05-01 JP JP81501281A patent/JPS57500761A/ja active Pending
- 1980-05-01 EP EP19810900873 patent/EP0050124A4/en not_active Withdrawn
-
1981
- 1981-05-01 CA CA000376670A patent/CA1175922A/en not_active Expired
- 1981-12-28 DK DK578981A patent/DK578981A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1981003250A1 (en) | 1981-11-12 |
| EP0050124A1 (en) | 1982-04-28 |
| EP0050124A4 (en) | 1982-09-03 |
| JPS57500761A (en) | 1982-04-30 |
| DE50124T1 (en) | 1983-01-05 |
| DK578981A (en) | 1981-12-28 |
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