EP1867074A1 - Method for carrying out a trouble-free change in frequency in a receiving system having a number of receivers operated in parallel - Google Patents

Method for carrying out a trouble-free change in frequency in a receiving system having a number of receivers operated in parallel

Info

Publication number
EP1867074A1
EP1867074A1 EP20060723953 EP06723953A EP1867074A1 EP 1867074 A1 EP1867074 A1 EP 1867074A1 EP 20060723953 EP20060723953 EP 20060723953 EP 06723953 A EP06723953 A EP 06723953A EP 1867074 A1 EP1867074 A1 EP 1867074A1
Authority
EP
European Patent Office
Prior art keywords
frequency
local oscillator
f3
current
characterized
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP20060723953
Other languages
German (de)
French (fr)
Inventor
Andreas Leistner
Carsten Huber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atmel Germany GmbH
Original Assignee
Atmel Germany GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to DE102005017005 priority Critical
Application filed by Atmel Germany GmbH filed Critical Atmel Germany GmbH
Priority to PCT/EP2006/002994 priority patent/WO2006105916A1/en
Publication of EP1867074A1 publication Critical patent/EP1867074A1/en
Application status is Withdrawn legal-status Critical

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Classifications

    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03JTUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J1/00Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
    • H03J1/0008Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
    • H03J1/0058Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor provided with channel identification means
    • H03J1/0083Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor provided with channel identification means using two or more tuners
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B15/00Suppression or limitation of noise or interference
    • H04B15/02Reducing interference from electric apparatus by means located at or near the interfering apparatus
    • H04B15/04Reducing interference from electric apparatus by means located at or near the interfering apparatus the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver, in a tape-recorder
    • H04B15/06Reducing interference from electric apparatus by means located at or near the interfering apparatus the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver, in a tape-recorder by local oscillators of receivers
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B2215/00Reducing interference at the transmission system level
    • H04B2215/064Reduction of clock or synthesizer reference frequency harmonics
    • H04B2215/066Reduction of clock or synthesizer reference frequency harmonics by stopping a clock generator

Abstract

The invention relates to a method for changing a frequency of a first local oscillator (60) in a receiving system (10), which has a first receiver (12) with a first local oscillator (60) and with a first frequency setting element (66), and a second receiver (14) with a second local oscillator (62) and with a second frequency setting element. The method is characterized in that, during a change in a frequency of the first local oscillator (60) from an actual frequency of the first local oscillator (60) to a target frequency, during which an actual frequency of the second local oscillator (62) is located between the actual frequency of the first local oscillator (60) and the target frequency, the following steps are carried out: switching off the first local oscillator (60); controlling the first frequency setting element (66) so that the first frequency setting element provides a first base value of a frequency setting quantity, said base value being assigned to the target frequency; switching on the first local oscillator (60), and; setting the frequency of the first local oscillator (60) to the target frequency. The invention also relates to a receiving system (10).

Description

A method of interference-free frequency changes in a Empfangssvstem with several parallel-operated receivers

In its method aspect, the invention relates to a method for changing a frequency of a first local oscillator in a receiver system comprising a first receiver with the first local oscillator and a first frequency control element and a second receiver with a second local oscillator and a second frequency control element.

In its apparatus aspect, the invention relates to a reception system comprising a first receiver with a first local oscillator and a first frequency control element, having at least a second receiver with a second local oscillator and a second frequency control element, and a frequency control device that a an alternating

Frequency of the first local oscillator from a current frequency of the first local

Controls the oscillator to a target frequency and / or regulates, wherein a current frequency of the second local oscillator between the current frequency of the first local oscillator and the target frequency.

Moreover, the invention relates to a computer program and a storage medium of a frequency control device of the receiving system.

Such a process, such a receiving system and such computer programs and storage media are known per se. Thus, for example during mobile reception of radio signals such as used several parallel-operating receiver in modern car radio. The so-called Radio Data System (RDS) transmits information, alternative frequencies soften the same radio program may be received in each case. The recipient can then review the various alternative frequencies to your reception quality and choose the best frequency for playback. It is advantageous to have a background receiver running alongside a Hörempfanger in the background, checking the alternative frequencies on the reception quality. Shows such a background receiver an alternative frequency with a better reception quality, for example, the listening receiver is switched to this frequency.

Such a background receiver can, for example, the first receiver and the listening receiver can be considered as the second receiver. In principle, there may be an interfering interaction between the two receivers in parallel, taking place in close proximity operation of two or more receivers each with its own local oscillator, when two local oscillators oscillate at similar frequencies. In the case of operating as a background receiver first receiver regularly occur to the fact that the first local oscillator settles to alternative frequencies and momentarily vibrates or when switching between two alternative frequencies near the frequency of the second local oscillator passes through its frequency. Left unchecked, it then because of the interactions mentioned interference.

It will be appreciated that the roles of the first and second receiver are interchangeable with respect to the undesired interaction. For example, the settling of the Hörempfängers disturbing to a new receiving frequency to receive the background Grand recipient and vice versa.

In conventional superheterodyne receivers a reception high frequency signal is downconverted by superimposition of oscillator signals to an intermediate frequency. The problem here is that local oscillators of the various receivers have to be very strongly decoupled from each other to avoid mutual interference. A known remedy provides for a separation of the frequency ranges of the local oscillators by using various sidebands before the mixing to the intermediate frequency of the superheterodyne receiver. Depending on the width of the tape used and location of the intermediate frequency this is not always possible, however. In some applications, the use of a sideband is favored because when using the other sideband the image frequency can fall, for example, in frequency ranges must be where expected strong EMI. Against this background, the object of the invention, in particular in the provision of a method and a reception system by which the disruptive interaction can be reduced at the parallel process of temporally more receivers each with its own local oscillators.

This object is achieved in a method of the type mentioned in that when changing a frequency of the first local oscillator from a current frequency of the first local oscillator to a target frequency, in which a current frequency of the second local oscillator between the current frequency of the first local oscillator and the target frequency, the following steps are performed: turning off the first local oscillator driving the first frequency adjusting member so that the first frequency control element one of the target frequency associated first base value of a frequency control value provides, turning on the first local oscillator, and adjusting the frequency of the first local oscillator to the target frequency.

Furthermore, this object is achieved in a receiving system of the type mentioned that the frequency control device switches off the first local oscillator so actuates the first frequency control element, provides that the first frequency control element one of the target frequency associated first base value of a frequency control value turns on the first local oscillator, and that the first receiver adjusts the frequency of the first local oscillator to the target frequency.

Furthermore, this object is achieved by a computer program which is programmed in the method of application, as well as a storage medium of a frequency control device of the receiving system, on which a computer program for use in the method is stored.

By doing so, the first local oscillator at the moment is turned off, in which the operatively coupled first frequency control element adjusts its control signal to the first base value. An illustration of the entire time course of the change in the control signal

therefore signal the first local oscillator will be omitted. Instead, only the signals of the first frequency adjusting member are formed in the signal of the first local oscillator in a first approximation, before and after the change from. Thus, the results from the interactions mentioned disturbances. In effect, this moves to the desired interference-free frequency change.

With regard to embodiments of the invention, it is preferable that the first base value is predetermined so that it leads to switching of the first local oscillator to a first base frequency which is above the frequency of the second local oscillator, when the target frequency is above the second local oscillator is, or is alternatively below the frequency of the second local oscillator, when the target frequency is below the frequency of the second local oscillator.

It is also preferred that the first base value is predetermined so that it leads to switching of the first local oscillator to a first base frequency which is further away from the current frequency of the second local oscillator as the target frequency.

This embodiment takes into account that can occur on the target frequency overshoot over time the frequency of the first local oscillator in the subsequent Einregelung. By initially larger frequency separation is largely avoided that the frequency of the first local oscillator at an overshoot of the frequency of the second local oscillator undesirably comes close. In other words, the first underlying ensures it were a safe distance that is greater than the expected overshoot.

It is also preferred that the step of Einregeins having a successively taking place setting at least one other base value, which leads to another base frequency that is closer to the target frequency than the first fundamental frequency.

By this configuration, the risk of resulting in overshoots interactions between the local oscillators is further reduced. In the described method for changing the oscillation frequency of an oscillator, other shock sensitive frequency ranges may in other receivers in the same way taken into account in the choice of the basic frequencies which are used for changing the oscillation frequency (for example, the reception frequencies of other receiver) adjacent to the oscillation frequency of the local oscillators become.

Therefore, it is preferred that in a receiving system with additional receivers, each of which has a local oscillator and a frequency control element, the first base value is predetermined so that it leads to a base frequency that is above the current frequencies of all the local oscillators, which is smaller than the target frequency, and which is below the current frequencies of all the local oscillators which are greater than the target frequency.

Through these features, the advantages mentioned above are also used in receiving systems having a total of n parallel operated receivers for supporting, where n is greater than the second

According to a preferred embodiment, wherein the first frequency control element is actuated as a function of the stored values ​​so are values ​​that are assigned to the target frequency, the current frequency of the first local oscillator and the actual frequency of the second local oscillator is stored, that the first base value providing in response to the stored values. In this way, differences in the tuning behavior of the local oscillators advantageously have no effect due to different frequency / control voltage characteristics.

Furthermore, it is preferable to check based on the stored values, whether the current frequency of the second local oscillator between the current frequency of the first local oscillator and the target frequency is, and only then to turn off the first local oscillator, if this is the case. In this way, a high reliability of the process is achieved even with a different tuning behavior of the local oscillators.

With regard to embodiments of the receiving apparatus is preferred that the first frequency actuator outputs a predetermined base value, which leads to switching of the first local oscillator to a first base frequency, the frequency from the current frequency of that local oscillator further comprises the shortest distance to the target frequency is removed as the target frequency.

It is further preferred that the receiving system uses a lower or an upper end of the tuning frequency of the first actuator as the first base value.

It is also preferable that the frequency control device predetermines at least one further successively underlying, which leads to another base frequency that is closer to the target frequency than the first fundamental frequency.

It is further preferred that the receiving system, shuts off a mixer which mixes a frequency of the first local oscillator having a different frequency during a change from the current frequency to the target frequency.

In a further embodiment, the receiving system further receiver on, each of which has a local oscillator and a frequency control element, wherein the frequency control unit outputs a first base value, which is predetermined such that it leads to a base frequency which is above the current frequencies of all the local oscillators is smaller than the target frequency, and which is below the current frequencies of all the local oscillators which are greater than the target frequency.

Preferably, the frequency control device is configured to store values ​​that are assigned to the target frequency, the current frequency of the first local oscillator and the actual frequency of the second local oscillator and to control the first frequency control element as a function of the stored values ​​so that the first base value in provides a function of the stored values.

The frequency control device is preferably formed in this case, to check using the stored values, whether the current frequency of the second local oscillator between the current frequency of the first local oscillator and the target frequency is, and only then to turn off the first local oscillator, if this is the case.

the advantages mentioned in the respective corresponding embodiments of method will become apparent to these embodiments of the receiver.

It is also preferred that the first receiver comprises, coupled to the first local oscillator for controlling the frequency of the first local oscillator phase locked loop.

Phase-locked loops are a way of rapid and accurate taking place regulation of the frequency of local oscillators.

It is preferable that the receiving system separates the phase locked loop and sets a minimum or maximum value from a tuning range of the phase-locked loop as a control variable for the first local oscillator.

Further advantages result from the description and the accompanying drawings.

It is understood that the features mentioned above and useful features to be explained not only in the respectively specified combination but also in other combinations or even alone, without departing from the scope of the present invention.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. The drawings show in schematic form:

FIG. 1 shows a receiving system with n = 2 recipients; Figure 2 is a beat frequency generator with features of the invention. FIG. 3 is time-correlated waveforms of various frequencies, amplitudes, and an activity state of the first local oscillator with a change of its frequency; Figure 4 is a graph showing the frequency of the first local oscillator at a frequency change, with an undesirable overshoot.

Figure 5 is a graph showing the frequency of the first local oscillator at a frequency change, which was carried out with corrective measures to reduce the overshoot. and

Fig. 6 is a circuitry concretized embodiment of the object of FIG. 2.

In detail, FIG. 1 shows the entirety of a receiving system 10 having a first receiver 12 and second receiver 14. The first receiver 12 includes a first high-frequency section 16, a first intermediate frequency section 18 and a first baseband and demodulating section 20. The design of the intermediate portion and the demodulation is not relevant to the invention. Therefore, the embodiments shown only to illustrate the invention in a possible technical environment serve. The first high frequency section 16 has a first antenna 22 are fed via the high-frequency signals or radio frequency signals into the first receiver 12th The inputted signals are amplified, optionally by a first low-noise amplifier 24 before being down-mixed in a first mixer 26 by mixing with a signal of a first local frequency generator 28 to an intermediate frequency, or be displaced. The period beginning with the output of the first mixer 26 first intermediate frequency section 18 may have a first intermediate-frequency filter 30, which may be realized for example as a bandpass filter with a bandwidth of 200 kHz. Further, the first intermediate frequency section 18 may include a first channel filter 32, which may have a bandwidth of 3.4 kHz, for example, and which serves for selection of the various transmission channels. The output signal of the first channel filter 32 is demodulated in this embodiment, in a first demodulator 34 and the demodulated signal is passed to a first terminal 36, which can be connected via further amplifier and signal processing stages, for example, with a speaker system. As already mentioned, the configuration of the blocks 18, 20 is not relevant to the implementation of the invention, m modern receivers, for example, is digitized by the intermediate frequency filter. Further signal processing then takes place in a digital signal processor (DSP).

Analogously, the second receiver 14 a second high frequency section 38, a second intermediate frequency section 40, a second baseband or demodulation section 42, a second antenna 44, a second low-noise amplifier 46, a second mixer 48, a second local frequency generator 50, a second

Intermediate frequency filter 52, a second channel filter 54, a second demodulator 56, and a second connection point 58. Again, the intermediate frequency filtering can alternatively be in digital form.

Such structure corresponds to a per se known receiving system, as used for example in car radios with a so-called antenna diversity function.

Each beat frequency encoder 28, 50 includes a local oscillator 60, 62, 50 of the principle can be disturbed by electromagnetic coupling the local oscillator of the other heterodyne frequency generator 28. Such electromagnetic coupling is indicated in Fig. 1 by the arrow 64.

Fig. 2 shows details of a configuration of the first heterodyne frequency generator 28 incorporating features of the invention. The first heterodyne frequency transmitter 28 comprises a first local oscillator 60 having a controllable output signal amplitude and a first frequency control element 66, which is controlled by an internal or external frequency control unit 68 which also controls the output amplitude of the oscillator 60th For this purpose, the frequency control device 68, for example, a storage medium on which a computer program for the application is stored in a method presented herein, wherein the computer program is programmed for use in any of these methods.

The first local oscillator 60 includes a tuning element 70, which is connected to an output 72 of the first actuator 66 and frequency with the frequency of the first local oscillator 60 can be tuned. Via an output 74 of the first local oscillator 60 is connected to the first mixer 26 and to an input 76 of the first frequency actuator 66th Between the output of the local oscillator 60 and the mixer 26 and the input 76, optional frequency divider can be used. its output signal amplitude is controlled by the frequency control device 68 via an input 78 of the first local oscillator 60, where the term control is meant to include also switching on and off of the first local oscillator 60th The first frequency control element 66 is in one embodiment of a control value generator 80, a base value generator 82 and a switch 84 which are respectively controlled by the frequency control device 68th

The not shown in Fig. 2 second local frequency generator 50 (see Fig. 1) is preferably similar to the first local frequency generator 28 constructed and has a second local oscillator 62 (Fig. 1) with a second tuning element and a second frequency control element for tuning the frequency of the second local oscillator 62.

The frequency control device 68 is connected to both the first local frequency generator 28 and to the second local frequency generator 50th In particular, the frequency control device 68 with the first frequency setting element 66 (or its components 80, 82, 84) and the second frequency control element (or its corresponding components) in order to control the frequency of actuators such that the local oscillators 60, 62 depending on an output signal produce with the respective desired frequency. Further, the frequency control device 68 is for turning on and off of the amplitude of the respective oscillator output signal with the first and preferably connected to the second oscillator.

For the following description Fl denote a current frequency of the first local oscillator 60 and F2 a current frequency of the second local oscillator 62. The frequency control device 68 controls the control value generator 80 and the switch 84 of the first frequency adjusting member 66 in such a way that the first local oscillator 60, a generates output signal using the current frequency Fl while the control value of the second frequency transmitter actuator is driven so that the second local oscillator 62 generates an output signal using the current frequency F2. Furthermore, F3 denote a target frequency of the first local oscillator 60th

Preferably, the values ​​of the frequencies Fl, F2 and F3 and these frequency values ​​are assigned values ​​(channel numbers, indexes, PLL divider values, etc.) known to the frequency control unit 68 and are stored in a RAM memory of the frequency control device 68th

For trouble-free change of frequency of the first local oscillator 60 from the current

by feeds Fl frequency to the target frequency F3, the frequency control device 68, the first frequency control element 66 controls preferably on a function of these stored values. Since the stored values ​​are assigned directly to the frequencies of the local oscillators, differences in the tuning behavior of the local oscillators advantageously have no effect due to different frequency / control voltage characteristics.

In the following, with reference to FIGS. 3 and explained in the figures 1 and 2 a first embodiment of a method for frequency hopping. In FIG. 3a, the

Frequency f of the output signal of the first local oscillator 60 depicted over the time t.

Fig. 3 c illustrates a switched between a state "on" and an off-state "off-changing activity state of the first local oscillator

60 and Fig. 3b illustrates high amplitudes and frequencies of its output signal during the frequency change.

Until time tl, the first local oscillator 60 is turned on (see Fig. 3 c, "on") and delivers accordingly a signal of frequency Fl and predetermined amplitude to the first mixer 26 (see FIG. 3b). The period of its output signal is the frequency Fl is thereby stabilized by a closed loop of the control value generator 80 of the first frequency actuator 66 and the first local oscillator 60 l / Fl..

For trouble-free change of the frequency of the first local oscillator 60 to the lying above F2 target frequency F3 of the first local oscillator 60 is turned off at the time tl from the lying below the frequency F2 current frequency Fl

(State "off in Fig. 3 c), so that its amplitude decreases and disappears in the extreme case, which corresponds to the zero signal in Fig. 3b. This corresponds to a first step of the process.

In case of failure in amplitude of the output signal of the first local oscillator 60 and each outgoing from that output signal levels of interference is eliminated. By switching off / elimination of the amplitude and the frequency stabilizing loop is separated in terms of effect.

Preferably, it is checked based on the stored values, whether the current frequency F2 is actually the second local oscillator 62 between the current frequency Fl of the first local oscillator 60 and the target frequency F3 before the execution of the first step. Only if this condition is met, the first local oscillator 60 are switched off and the steps described below carried out in this case. Since the stored

Values ​​are directly assigned to the frequencies of the local oscillators, differences in the tuning of the local oscillators have behaved as a result of different frequency / control voltage characteristics advantageously no influence on the method, so that even a high reliability is achieved.

When switched off the first oscillator 60 in a second step over a period delta_t2 the natural frequency of the first local oscillator 60 via a control intervention to be

70 tuning to the target frequency F3 or an approximate value or underlying F3 A adjusted for regulation of the target frequency F3. In this case, the stored by the

Values ​​dependent underlying at a corresponding position of the switch 84 through the

Base value generator 82 is provided. The adjustment of the frequency of the first local oscillator 60 is illustrated in FIG. 3a by the dashed arrow 86. While passing through the

(Internal) frequency of the first local oscillator 60, the frequency F2 of the second local

Oscillator 62 that no interfering with the extreme case of vanishing amplitude so

Coupling can be effected from the first local oscillator 60 to the second local oscillator 62nd

Only after the (internal) has undergone frequency of the first local oscillator 60, the frequency F2 of the second oscillator 62, the first oscillator is switched on again in a third step, at the time t3 60 where the amplitude of its output signal in the ideal case at the target frequency F3 soars , The period duration of its output signal is then 1 / F3. It should be noted that the period of the oscillator signal is not drawn to the same time scale as the frequency changes. Usually, such take. However, as the transient from the underlying F3A to the target frequency F3, so the frequency change after a time point t4, a few ms, the oscillator period is, for example, only 10 ns long.

Since the frequency-stabilizing loop was separated by turning off the first local oscillator 60 and by operating the changeover switch 84, initially arising after the restart of the first local oscillator 60 typically deviates from the target frequency F3, determined by the underlying or control value frequency F3A , In order to eliminate the deviation, an adjustment of the frequency reference of the frequency stabilization loop to the target frequency F3 takes place in a fourth step, which is performed from a time t4, before resetting of the switch 84 in the illustrated in FIG. 2 switching state. Since the resetting of the change-over switch 84 closes in conjunction with the restarting of the first local oscillator 60, the frequency-stabilizing loop of the first oscillator 60 and control encoder 80 again, the deviation is corrected so that the output signal of the first local oscillator 60 to the desired target frequency F3 adjusts. It will be understood that the fourth step can be carried out parallel to the third step both before and after.

By doing so, the first oscillator 60 is turned off at the moment when its tuning element 70 is brought into a state in which the first oscillator 60 oscillate at the frequency F2 of the second oscillator 62 and would cause disturbances in the second receiver fourteenth Characterized interfering Einkoppmngen 64 are avoided in the second receiver fourteenth

This method can be used in a further development for more than n = 2 are simultaneously operated receiver. Ih this case, the tuning element 70 must be in the second step to a position to be placed, which leads to an oscillation frequency F3 A, which is above the oscillation frequencies of all the second local oscillators, which are operated at a frequency below the target frequency F3 and below the oscillation frequencies of all second local oscillator is operated at a frequency above F3.

In both cases - two or more receivers - it may happen in spite of the proposed method that the first local oscillator 60 by overshoot when activating the frequency stabilization loop for a short time in the vicinity of the frequency F2 of the second local oscillators oscillates as shown by the Figure is illustrated. 4, apply to the rest, the explanations of FIG. 3. in particular, Fig. 4 shows an overshoot with a frequency bandwidth FA, by the underlying F3A to over a frequency F2 of a second local oscillator 62 is sufficient. Since the first local oscillator 60 oscillates already again with a non-negligible amplitude in the settling of the frequency stabilization loop of the overshoot FA (see Fig. 1) could lead to disturbing couplings 64 in a second local oscillator 62.

This occurs under certain circumstances a problem can be avoided that first a frequency reference F3B the frequency stabilization loop is set in the fourth step, which is sufficiently close to the underlying F3A characterized. This bandwidth FA of an overshoot that may occur is reduced and interfering interactions with other local oscillators in other receivers are avoided.

Subsequently, the frequency value of the frequency stabilization loop can, if necessary, in several steps via intermediate values ​​F3B, be adjusted to the target frequency F3 F3C, resulting in a stepwise forming transient to the target frequency F3 results without local oscillators to be disturbed in other receivers. Such, success forming via intermediate values ​​F3B, F3C transient is shown in Fig. 5.

This approach assumes that the frequency bandwidth FA of the Uber vibrator when activating the frequency stabilization loop, respectively, is lower in the stepwise diminishing towards its frequency reference values ​​to the target frequency F3, if the distance from the underlying F3A small to an intermediate value F3B than the distance of the underlying F3A is chosen by the target frequency F3. This is, for example, when using a phase locked loop as a frequency stabilizing loop is usually the case.

During the entire process for the frequency change of the mixer can be switched off or the signal transmission to be interrupted by the superposition frequency generator to the mixer, in order to avoid interference with other system components by the appended during the frequency change at the mixer frequencies. The frequency components at the mixer may differ from that of the local oscillator, for example when using a frequency divider between the local oscillator and mixer.

The described method can also be used when two receivers are present in a system, the temporary received for antenna diversity reception on the same frequency and this state is achieved, at a first receiver of the associated local oscillator is disabled and the oscillator signal of another receiver is used. The first receiver may be tuned by the described method to a different frequency, without interfering with the other receiver. The first step of the process described above is superfluous here, because the oscillator of the first consignee is already switched off.

When two receivers each have a position above (or below) the control range can be used to used in the second step of the process described above, positions of the tuning element 70, which is used for tuning to the frequencies in the reception band.

The flow control for the described tuning methods can be implemented as software running on a microcontroller, for example, which has a control bus to access the appropriate components in the receiver. Alternatively, a realization in hardware in an integrated circuit recipient is possible.

Fig. 6 shows the subject of FIG. 2 with further details a configuration of the first frequency adjusting member 66 with elements of such a phase-locked loop as a rule, it wertgeb 80, together with further details of an embodiment of the first local oscillator 60. In this case, like reference numerals designate the same or functionally identical objects ,

The first local oscillator 60 is, for example, as a voltage controlled oscillator (VCO), realized with a parallel resonant circuit comprising inductive (88) and capacitive (90, 92, 94, 96, 98) alternating-current resistors 88, 90 ... 98, wherein at least one capacitance diode or varactor diode 96, 98 serves as a tuning element 70th The capacity of such a capacitance diode 96, 98 is known, can be varied by varying a voltage applied across their control DC voltage v_tune. Since the frequency of such a resonant circuit is dependent on the values ​​of the concerned inductive and capacitive impedances 88, 90, ..., 98, forms a change in the control direct voltage v_rune known in a predictable change in the oscillating circuit frequency, and thus in a controllable change in the beat frequency from. so that the control direct voltage v_tune represents a frequency control value.

The resonant circuit is further coupled to a power supply switched on and off, the light emitted from the resonant circuit as well as Joule dissipation and the extracted from the mixer output in correct phase replaced. . In the embodiment of Figure 6, this is accomplished by transistor 100, which via a switch between the "+" and - there is a supply voltage and controlled by a portion of the AC voltage appearing across the resonant circuit "." The switch for switching on and off of the power supply and the first local oscillator 60 is controlled by the frequency control device 68th According to the above description of the method, the frequency control device 68 controls - preferably after checking the condition Fl <F2 <F3 - the switch so that it is opened in step 1 and then closed again in step 3 of the process, so that the first local oscillator 60 is between times tl and t3 turned off, while it is otherwise switched on (see Fig. 3 c).

In such an implementation, the first local oscillator 60, the tuning is the

Frequency of the resonant circuit, independently from the switching on / off of the first local oscillator 60, that is, independent of the engagement of its oscillation amplitude. At the

Turning on / off of the first local oscillator 60, the amplitude of its AC changes

Output signal when changing the tuning frequency of its AC v_tune the

Output signal. Switched to a first local oscillator 60, then establishes a

Vibration to the predetermined by the tuning element 70 and the other elements of the resonant circuit frequency. The amplitude increases during this

However, power-on, the frequency and period remains almost constant.

The tuning v_rune is provided by the first frequency control element 66, which is activated so-controlled by the frequency control unit 68 depending on the stored values ​​as to give at the output of first local oscillator 60 the respective desired frequency. To this end, the control value encoder 80 of the first actuator frequency a programmable frequency divider 102, a reference frequency generator 104 and a phase frequency detector (PFD) 106. The frequency output from the first local oscillator 60 is divided down by the frequency divider 102 and compared with a reference frequency output from the encoder 104 reference frequency. Depending on whether advancing pulses of the divided oscillator signal pulses of the reference signal, or lag, of the phase frequency detector 106 controls to a downstream charge pump 108 to issue up charge pulses or down-charging pulses which charge a capacitor of a loop filter 110, or discharged, and thus the Schleifenfϊlter of the provided control DC v_tune change gradually.

In an alternative embodiment, can also be dispensed to a separate base transmitter 82nd In this case, it may be considered to set a base value for the target frequency directly by changing the factor N in the programmable frequency divider 102 .. But this is hardly possible because no oscillator signal at the input of the N divider is present when the base value is set. Therefore, the base value is preferably adjusted directly through targeted control of the current sources in the charge pump 108th The tuning range of the phase locked loop is then proportional to the difference of the voltage developed across the loop filter capacitor when fully charged and full discharge through the power sources.

As shown in Fig. 6, the programmable frequency divider 102, the changeover switch 84 and the base value generator 82 are controlled by the frequency control unit 68 that these elements in dependence on the stored values ​​associated with the frequency values ​​Fl, F2 and F3 corresponding to the above the method described so controls that the first frequency control element 66 provides the dependent from the stored values, and possibly the first base value dependent on the stored values ​​further underlying.

Claims

claims
1. A method for changing a frequency of a first local oscillator (60) in a receiving system (10) comprising a first receiver (12) with the first local oscillator (60) and a first frequency control element (66) and a second receiver (14) with a second local oscillator (62) and a second frequency control element, comprising characterized in that on a target frequency during a change of a frequency of the first local oscillator (60) from a current frequency (Fl) of the first local oscillator (60) (F3) in which a current frequency (F2) of the second local oscillator (62) between the current frequency (Fl) of the first local oscillator (60) and said target frequency (F3) is located, the following steps are performed: turning off the first local oscillator (60 provides), driving said first frequency control element (66) so that the first frequency control element (66) one of the target frequency (F3) the associated first base value of a frequency control value (v-tune) , Turning on the first local oscillator (60), and adjusting the frequency of the first local oscillator (60) to the target frequency (F3).
2. The method according to claim 1, characterized in that the first base is so predetermined value, that it leads to switching of the first local oscillator (60) to a first base frequency (F3A) located above the current frequency (F2) of the second local oscillator (62), when the target frequency (F3) above the current frequency (F2) of the second local oscillator (62), or alternatively, below the current frequency (F2) of the second local oscillator (62) when the target frequency (F3) below the current frequency (F2) of the second local
Oscillator (62).
3. The method of claim 1 or 2, characterized in that the first base value is predetermined so that it leads to switching of the first local oscillator (60) to a first base frequency (F3A), further from the current frequency (F2) is removed the second local oscillator (62) as the target frequency (F3).
4. The method according to any one of claims 1 to 3, characterized in that the step of Einregeins having a successively taking place setting at least one further Underlying to another base frequency (F3B, F3C) results that are closer to the target frequency (F3) is as the first base frequency (F3A).
5. The method according to any one of claims 1 to 4, characterized in that further noise-sensitive frequencies in the choice of the first base frequency (F3A) are taken into account.
6. A method according to claim 4, characterized in that in a receiving system (10) having additional receivers, each of which has a local oscillator and a frequency control element, the first base value is predetermined such that it leads to a base frequency which is above the current frequencies of all the local oscillators is smaller than the target frequency, and which is below the current frequencies of all the local oscillators which are greater than the target frequency.
7. The method according to any one of the preceding claims, characterized by a step of storing values ​​corresponding to the target frequency (F3), the actual frequency (Fl) of the first local oscillator (60) and the current frequency (F2) of the second local oscillator ( 62 are assigned), wherein the first frequency setting element
(66) is controlled as a function of the stored values ​​so that it provides the first base value depending on the stored values.
8. The method according to claim 7, characterized in that it is checked based on the stored values, whether the current frequency (F2) of the second local oscillator (62) between the current frequency (Fl) of the first local oscillator (60) and the
Target frequency (F3), and the first local oscillator (60) is only switched off if this is the case.
9. The receiving system (10) comprising a first receiver (12) with a first local oscillator (60) and a first frequency control element (66), at least a second receiver (14) having a second local oscillator (62) and a second frequency control element, and comprising a frequency control device (68) including a change of a frequency of the first local oscillator (60) from a current frequency (Fl) of the first local oscillator (60) to a target frequency (F3) controls and / or regulates, a current frequency ( F2) of the second local oscillator (62) between the current frequency (Fl) of the first local oscillator (60) and said target frequency (F3), characterized in that the frequency control device (68) switches off the first local oscillator (60) first frequency control element (66) so controls that the first
Frequency control element (66) one of the target frequency (F3) the associated first base value of a frequency control value (V tune) provides, turns on the first local oscillator (60) and that the first frequency control element (66) the frequency of the first local oscillator (60) to the target frequency (F3) adjusts.
10. The receiving system (10) according to claim 9, characterized in that the first frequency control element (66) outputs a predetermined base value, which leads to switching of the first local oscillator (60) to a first base frequency (F3A), the further current from the frequency (F2) of that local oscillator (60) whose frequency has the smallest distance to the target frequency (F3), is removed as the target frequency (F3).
11. The receiving system (10) according to claim 9 or 10, characterized in that it uses a lower or an upper end of the tuning frequency of the first actuator (66) as a first base value.
12. The receiving system (10) according to any one of claims 9 to 11, characterized in that the first frequency control element (66) predetermines successively at least one additional base value that to another base frequency (F3B, F3C) leads that are closer (on the target frequency F3 ) than the first base frequency (F3A).
13. The receiving system (10) according to one of claims 9 to 12, characterized in that it comprises a mixer (26) which mixes a frequency of the first local oscillator (60) with a different frequency (during a shift from the current frequency Fl ) (on the target frequency F3) turns off.
14. The receiving system (10) according to any one of claims 9 to 13, characterized in that it comprises more recipients, each having a local oscillator and a frequency control element, wherein the first frequency control element (66) has a first
outputting base value that is predetermined so that it leads to a base frequency that is above the current frequencies of all the local oscillators, which are smaller than the target frequency, and which is below the current frequencies of all the local oscillators which are greater than the target frequency.
15. The receiving system (10) according to any one of claims 9 to 14, characterized in that the first receiver (12) with the first local oscillator (60) for controlling the frequency of the first local oscillator coupled (60) phase-locked loop (102, 104 , 106, 108, 110).
16. The receiving system (10) according to claim 15, characterized in that it the phase control loop (102, 104, 106, 108, 110) separates and a minimum or maximum value from a tuning range of the phase locked loop (102, 104, 106, 108, 110 ) sets as a control variable for the first local oscillator (60).
17. The receiving system (10) according to one of claims 9 to 16, characterized in that the frequency control device (68) is configured to store values ​​corresponding to the target frequency (F3), the actual frequency (Fl) of the first local oscillator (60) and the current frequency (F2) of the second local oscillator (62) are associated, and the first frequency control element (66) in dependence on the stored values ​​to be driven so that it provides the first base value depending on the stored values.
18. The receiving system (10) according to claim 17, characterized in that the frequency control device (68) is configured to check based on the stored values, whether the current frequency (F2) of the second local oscillator (62) between the current frequency (Fl) the first local oscillator (60) and the target frequency (F3), and only then to turn off the first local oscillator (60) when this is the case.
19. The receiving system (10) according to one of claims 9 to 18, characterized in that the frequency control device (68) is programmed for use in one of the processes according to claims 1 to eighth
20. Computer program, characterized in that it is programmed for use in one of the processes according to claims 1 to eighth
21 storage medium of a frequency control device (68) a receiving system (10), characterized in that a computer program for use in one of the processes of claims 1 to 8 is stored on the storage medium.
EP20060723953 2005-04-07 2006-04-01 Method for carrying out a trouble-free change in frequency in a receiving system having a number of receivers operated in parallel Withdrawn EP1867074A1 (en)

Priority Applications (2)

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DE102005017005 2005-04-07
PCT/EP2006/002994 WO2006105916A1 (en) 2005-04-07 2006-04-01 Method for carrying out a trouble-free change in frequency in a receiving system having a number of receivers operated in parallel

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EP (1) EP1867074A1 (en)
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US20080090542A1 (en) 2008-04-17
CN101156339A (en) 2008-04-02

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