Tuning Control Arrangement

• US 20080186114A1
• Filed: 10/17/2005
• Published: 08/07/2008
• Est. Priority Date: 04/05/2005
• Status: Active Grant

• Current Assignee: George Hedley Storm Rokos
• Original Assignee: George Hedley Storm Rokos
• Inventors: Rokos, George Hedley Storm
• Granted Patent: US 8,022,789 B2
• Time in Patent Office: Days
• US Class Current: 334/15
• CPC Class Codes: H03B 5/1228 the amplifier comprising one or more field effect transistors
• CPC Class Codes: H03B 5/1253 the transistors being field-effect transistors
• CPC Class Codes: H03B 5/1293 having means for achieving a desired tuning characteristic, e.g. linearising the frequency characteristic across the tuning voltage range
• CPC Class Codes: H03J 3/04 Arrangements for compensating for variations of physical values, e.g. temperature

Abstract

A tuning arrangement for a resonant circuit, the tuning arrangement having an output reactance dependent upon a plurality of input applied signals one of which is an input tuning signal, and comprising: an array of tuning circuits connected in a network whose output reactance is used to control the resonance frequency of the resonant circuit, each tuning circuit having a control input and having a reactance which varies in dependence upon the value of a control signal applied to the control input; means for generating a plurality of different control signals for application to the control inputs of the tuning circuits; and each such control signal varying substantially linearly with the input tuning signal throughout a predetermined range specific to that control signal, so that the frequency response of the resonant circuit to the input tuning signal is substantially linear throughout a desired range of the input tuning signal. The tuning circuits are preferably variable reactance elements such as MOS varactors and further control signals can be applied to control higher order components.

Claims

1. A tuning arrangement for a resonant circuit, the tuning arrangement having an output reactance dependent upon a plurality of input applied signals one of which is an input tuning signal, and comprising:

an array of tuning circuits connected in a network whose output reactance is used to control the resonance frequency of the resonant circuit, each tuning circuit having a control input and having a reactance which varies in dependence upon the value of a control signal applied to the control input;

means for generating a plurality of different control signals for application to the control inputs of the tuning circuits; and

each such control signal varying substantially linearly with the input tuning signal throughout a predetermined range specific to that control signal,

so that the frequency response of the resonant circuit to the input tuning signal is substantially linear throughout a desired range of the input tuning signal.

2. A tuning arrangement according to claim 1 in which the network is a parallel network.

3. A tuning arrangement according to claim 1 comprising at least one control input that has more than one control port, and wherein the control signal applied to at least one control port is dependent upon the input tuning signal.

4. A tuning arrangement according to claim 1 in which the gradients of the linear dependencies of any or all of the control signals on the input tuning signal are substantially reduced in a region where the tuning gradient of the resonant frequency with respect to the control signal is small compared with the peak gradient of the resonant frequency with respect to that control signal.

5. A tuning arrangement according to claim 1 in which the gradients of the linear dependencies of at least one of the control signals on the input tuning signal are substantially the same, said gradient including the effect of any dependency of the other input applied signals on the input tuning signal.

6. A tuning arrangement according to claim 1 in which the gradients of the linear dependencies of at least one of the control signals on the input tuning signal are increased in a region where the tuning gradient of the resonant frequency with respect to a control signal is reduced compared with the peak gradient of the resonant frequency with respect to that control signal, the increase in the gradient being such as to allow the linear tuning range of the resonator with respect to the input tuning signal to be increased relative to what would be possible without such an increase .

7. A tuning arrangement according to claim 1 in which the input tuning signal is developed from a prior tuning signal, the response of the input tuning signal being non-linear with respect to the prior tuning signal for signals outside the range where the tuning response is linear with respect to the input tuning signal, the non-linear response being such as to extend the linear range of the tuning response with respect to the prior input signal.

8. A tuning arrangement according to claim 1 comprising means for determining or adjusting the input applied signal using digital information stored in a nonvolatile electronic memory.

9. A tuning arrangement according to claim 1 comprising means for adjusting the response of the control signals to any of the input applied signals using digital information stored in a non-volatile memory.

10. A tuning arrangement according to claim 8 wherein the adjusting means serves to maintain constancy of the overall tuning response of the resonance frequency to the input tuning signal in the presence of differing oscillator and tuning parameters.

11. A tuning arrangement according to claim 1 comprising means for modifying at least one of the input applied signals such as to maintain constant tuning frequency response of the resonant circuit to the input tuning signal over the desired tuning range and/or over a desired temperature range.

12. A tuning arrangement according to claim 1 comprising means for modifying at least one of the input applied signals as a function of temperature to correct for temperature dependence.

13. A tuning arrangement according to claim 1 wherein the number of tuning circuits in the network is substantially more than the plurality of input applied signals.

14. A tuning arrangement according to claim 1 wherein the tuning circuits comprise MOS Varactors .

15. A tuning arrangement according to claim 11 wherein the means for generating control signals comprises a distribution network to which a plurality of input applied signals is applied to adjust the relative distribution of the gains from the input applied signals to the control signals wherein the number of input applied signals is related to the number of independent control parameters required.

16. A tuning arrangement according to claim 1 wherein the means for generating control signals comprises a resistive network in the form of a ladder, wherein the input applied signals are applied to the top and bottom of the ladder, and the control signals are derived from the potentials on one side of the ladder, the resistances in the ladder being arranged such that the proportions of the individual input applied signals that are derived at the control ports result in the creation of adjustments to the tuning response that are polynomial functions of the input tuning signal level, these functions being quasi-orthogonal functions of the third order or less for input applied signals that are independent of the input tuning signal, and application of input applied signals that are dependent on the input tuning signal to the feet or top arms results in a modification to the tuning response that has a power dependency that is one order higher than this, whereby the tuning response to the input tuning signal can be adjusted and set to be substantially linear.

17. A tuning arrangement according to claim 1 comprising a chain of resistors connected in series at nodes, wherein the signals at the nodes comprise the plurality of control signals for the tuning circuits, wherein a plurality of the nodes are connected also to the vertices of a star or stars of resistors, the central node of each star being connected to all the resistors comprising that star as well as to an intermediate potential that is dependent on an input applied signal, and the ends of the resistor chain to further such potentials, all of these potentials being adjustable under the control of non-volatile digital memory such that the tuning response of the oscillator to an applied tuning signal can be adjusted and set to be substantially linear.

18. A tuning arrangement according to claim 15, utilising a resistor network whose values are defined so that signals that are linearly dependent signals on the input applied signals may be applied to control points within the resistor network such that one input applied signal adjusts frequency offset, another adjusts at most offset and linear variation of tuning sensitivity with signal level, and that, for each order of response to be adjusted, there is a control point that has response up to that order, but has substantially no response for higher orders.

19. A tuning arrangement according to claim 15 in which the adjustment to the signals at the control points of the network comprise offsets that are independent of the level of the input tuning signal.

20. A tuning arrangement according to claim 15 in which the signals at the control points include components that are linearly dependent on a temperature-dependent signal, the relationship between these components being predetermined or adjustable to maintain the response of the dependence of the frequency of the oscillation signal on the tuning input signal to be substantially linear and constant over the required temperature range.

21. A tuning arrangement according to claim 14 wherein pairs of MOS varactor elements are connected back-to-back, with either the gate or well of the first element of the pair being electrically connected to the identical terminal of the second element of the same pair, the major component of the input applied signal part of the control signal being applied via that terminal, and the resonance signal being applied between the other two varactor terminals of the MOS varactor pair.

22. A tuning arrangement according to claim 1 wherein the gain from the input tuning signal to at least some of the control inputs may be individually pre-adjusted.

23. (canceled)

24. A method of tuning electronic components, the method comprising splitting an input applied signal to generate a plurality of individual control signals of different values, applying each different individual control signal to the control input of a tuning circuit that is one of an array of tuning circuits, each of whose output reactance varies in dependence upon the value of the control signal applied to its control input.

25. A method of tuning according to claim 24 using a tuning arrangement comprising:

an array of tuning circuits connected in a network whose output reactance is used to control the resonance frequency of the resonant circuit, each tuning circuit having a control input and having a reactance which varies in dependence upon the value of a control signal applied to the control input;

means for generating a plurality of different control signals for application to the control inputs of the tuning circuits; and

each such control signal varying substantially linearly with the input tuning signal throughout a predetermined range specific to that control signal,

so that the frequency response of the resonant circuit to the input tuning signal is substantially linear throughout a desired range of the input tuning signal.

26. A method of tuning a quartz crystal oscillator using the method of claim 24.