DE2251388A1 - HIGH FREQUENCY DIVIDER - Google Patents

Description

Patent attorney
7 Stuttgart 3o
Short street 8

CH. Petit jean - M.E. L. Marchand -2-1

STAHDAED ELEGTEIC COBPOEATION, NEW XOEK

High frequency divider

The invention relates to a high frequency divider the output of which can be either the input frequency or the input frequency given by η.

Frequency divider required for frequencies above 5oo MHz in particular with frequency processing circuits, also called synthesizers. The! Frequency processing is generally a device with which a spectral line of a discontinuous Spectrum of predetermined stable frequencies is obtained, the stable frequencies multiples a reference frequency generated by / by a highly stable reference generator.

5.1o. 1972

J Ü <3 8 I B / I> 7 S 5

C.H. Petitjean -2 -1 - 2 -

The frequency spectrum is often generated by a voltage-controlled oscillator, whose Frequency F is divided by N using a variable divider. The signal with the frequency F / N is compared in frequency and phase with a reference signal F in two comparators · The output signals this comparator goes to the voltage controlled oscillator (VCO) to this so that it is on the frequency F = N.F swings. The first voltage is used for coarse adjustment and the second for fine adjustment, i.e. for phase synchronization.

There is a synthesizer with digital dividers above 15 ° MHz are no longer usable, it is necessary to add a number of multipliers to the output of the synthesizer downstream if higher frequencies are to be generated. With the TACAN system, which runs at 1 GHz is therefore a multiplication factor based on a maximum synthesizer frequency of 125 MHz of 8 required.

It is known, however, that multipliers always change the useful / interfering signal ratio.

In the case of the digital synthesizers mentioned, the interfering signals are single frequencies and thermal Rush. This modulates the signal in amplitude or phase. The interfering signals are coming on the error voltage of the phase comparator. That Ratio of useful / audible signal that is output at the Synthesizer is 60 dB, for example, can turn out to be

BATH ORIGINAL

3 0 9 β 18/0755

C.H. Petitjean 2-1 - 3 -

by three "successive" multiplications with change the factor 2 to the value 4o dB.

It is known to produce a subharmonic vision F / n a frequency F to use an oscillator with negative resistance, its resonant circuit about is tuned to the subharmonic F / n and the is synchronized by the frequency F. As a ne-. gative resistances are used for this purpose, capacitance diodes. .

In the case of a capacitance diode, the capacitance changes according to the applied bias. This one . parametric effect is used like this:

The capacitance diode is used as a capacitance in a parallel resonant circuit, which is based on a Frequency is tuned very close to F / n and to which the energy is supplied as a so-called pump frequency F. will. Under these conditions, the capacitance diode behaves like a at the frequency F / n negative resistance. In this way, vibrations are triggered that are sustained and synchronized with the frequency F.

If the frequency F is highly stable here, then this also applies to the frequency F / n.

If the output frequency is to be very stable, then a good decoupling of the input frequency is necessary F required by the output frequency F / n.

-4-

BATH ORIGINAL

309 8 1 8 / 07B5

This decoupling is generally achieved by circulators containing ferrites. These but have the disadvantage that they are not used when the ambient temperature fluctuates greatly 'can. They are namely very sensitive to the very low temperatures of aircraft on-board equipment appear.

It is therefore the object of the invention to provide a high-frequency divider that is in a large Temperature range works reliably and the. through the closer control signals from one Frequency can be switched to the other frequency.

This Aufge.be is achieved according to the invention in that a parametric oscillator on a subharmonic F / n of the input frequency F oscillates, is provided, which consists of a parallel oscillating circuit and a series connection of a capacitance diode with a Series oscillating circuit also matched to F / n exists and to which the input frequency F is fed as a pump frequency that is parallel to the capacitance diode of the oscillator is a first switching element, which is from a hoc ho intimate to a low resistance State is switchable and that the oscillation with the frequency F / n via a tap of the parallel resonant circuit inductance removed and can be bridged by a second switching element which can be actuated simultaneously with the first switching element Bandpass is fed to the output.

ORIGINAL BATHROOM 309818/0755

Further developments of the invention are set out in the subclaims removable.

The invention will now be based on the drawings "for example explained in more detail. Show it:

3? Ig. 1 a radio frequency divider and

2 shows a further development of the arrangement according to B ¹ Ig. 1.

The main parts of the frequency divider are in IPig. 1 contained within the dashed rectangle marked I. Located in this rectangle themselves:

a capacitance diode 1, the input 2 of which is connected to ground 6 > a series resonant circuit consisting of an inductance 4 and a capacitance 5 is connected, and '

a parallel resonant circuit consisting of a capacitor 7 and an inductance 8 which is connected between the output 3 of the capacitance diode 1 and ground 6.

The capacitor 7 is adjustable and the inductance 8 is designed as an autotransformer whose connection

-6-

BATH ORIGINAL

309 818/0755

tap 9 is connected to a line 1o which leads out of the rectangle I.

The series resonant circuit from parts 4 and 5 has a resonance frequency of P / n, therefore input 2 of the capacitance diode is at this frequency 1 in terms of high frequency to ground.

The static capacitance of the varactor diode 1 is adjusted by a bias, such as will be described below.

The parallel connection of this static capacity the capacitance diode 7> with a possible capacitance between the tap 9 and ground 6, the because of the line 1o could occur ^ and the Inductance 8 has the resonance frequency F / n.

With a suitable choice of tap 9, it is possible to the real part of the grooveζimpedanζ into a resistor to transform, which is therefore between the output 3 and ground 6 and the capacitance diode 1 properly loaded, with the maximum efficiency being reached at the frequency F / n.

Located between an input 11, to which the frequency F reaches, and the input 2 of the rectangle I. themselves:

a bandpass filter 12 with the center frequency F and a bandwidth of 2F;

-7-

BAD ORiGfNAL

309818/0755

a coupling capacitor 13, which for the frequencies F and F / n a Short circuit represents and

a line 14 from the capacitor 13 to the input 2 of the rectangle I. leads.

On the output side of the rectangle I connected to the line 1o are:

in series with line 1o, an adjustable capacitor 15;

an adjustable capacitor 16 placed between the other electrode of the capacitor 15 "and ground 6 lies;

a bandpass filter 17 with the center frequency P / n and a bandwidth of 2F / n and

an output terminal 18 at which either the frequency F or the frequency F / n occurs.

The bandpass filter 17 in Fig. 1 consists of two L-members, each of which has a series capacitor 17a and a parallel resonant circuit 17b, whose lower end is connected to ground.

-8th-

BATH ORIGINAL

309818/07 5 5

The input 2 of the rectangle list via a line 19 with an electrode of a decoupling capacitor 2o connected, which represents a short circuit for the frequencies F and F / n. The other electrode of the capacitor 2o is connected to the input of a first PIN diode, the output of which with the Output 3 of the capacitance diode 1 is connected via a line 22.

The common point of capacitors 15 and 16 is connected via a line 23 to the input of a second PIN diode 24-, the output of which is connected to is connected to the output of the filter 17 via a line 25

The varactor diode 1 and the PIN diodes 21 and 24 received their bias from DC voltage sources shown in rectangle II of FIG are.

Inside the rectangle II are: ■

a DC voltage source 26, the negative terminal of which is connected to the input 2 of the capacitance diode 1 via a resistor 27, a choke coil 28, a line 19a and the line 19 and the positive terminal of which is connected to a ground line 6 ¹ , which is connected to the ground 6 via a line 6 "is connected. A decoupling capacitor 29 is located between the common point of parts 27 and 28 and the ground line 6 ';

2 nights 9 ö 1 8/0 7 5 l

a (Reichspannungsquelle 3o, which on two values can be switched, one of which is only slightly positive and the logical one "0" corresponds and the other is a few volts and corresponds to the logic "1".

The negative terminal of the voltage source 3o is connected to the ground line 6 ¹ and its positive terminal is connected to the input of the PIN diode 21 via a resistor 31, a choke 32 and a line 33. A decoupling capacitor 34- is located between the common point of 31 and 32 and the ground line 6 '.

The positive terminal of the voltage source 3o is a choke 36 and a line 37 via a resistor 35 j. connected to the input of the PIN diode 24-. A decoupling capacitor 38 lies between the common point of 35 " ¹¹¹ Id 36 and the ground line 6 '.

Parts 27, 28 and 29 as well as 31, 32, 34 and 35, 36, 38 are low-pass filters that connect to input 2 of the capacitance diode 1, the input of the PIN diode 21 and the input of the PIN diode 24- are connected upstream and which ensure that due to their high resistance, only a very small stand for high frequencies Part of the high frequency currents of frequencies F and F / n can flow off.

-io-

BATH ORIGINAL

309818/0756

It should be noted that the capacitor 2 is used to decouple the bias voltage for the capacitance diode 1 and from the bias voltage for the PIN diode 21 is used.

Correspondingly, the capacitor 13 decouples the varactor diode 1 direct current from the input stages of the high frequency divider, so that direct current from the voltage source 26 is only about the series connection of the elements 27ι 28, 1 and 8 flows. The voltage of the voltage source 26 and / or the resistor 27 are adjusted so that the static capacitance of the capacitance diode is available.

The arrangement according to Fig. 1 works as follows:

1. If the voltage source 3o has a low Voltage corresponding to the logic "0" supplies is the series connection of capacitor 2o and PIN diode 21, the parallel to the capacitance diode 1, high resistance. The varactor thus works 1 as an electronically variable capacitor. The signal from the input 11 with the frequency F therefore also causes Using the capacitance diode 1, the generation of oscillations with the frequency F / n. These oscillations cannot reach the input 11, since they are caused on the one hand by the series oscillating circuit from FIGS

-.11-

309918/0755

and on the other hand blocked by the bandpass filter 12 with the band center frequency F. will.

den! "all that the series oscillating circuit from 4 and 5 oscillates exactly to 3F / n the bandpass filter 12 can even be omitted. However, it is required if F contains) Certain limit values can be changed by a frequency F and if the arrangement from 4 and 5 then swings to F / n. If F is variable, then it is necessary to that the capacitor 7 is adjustable, so that the arrangement ■ from 1,7 and 8 exactly swings to F / n.

The frequency F and F / n get on the line 1o.

The bandpass filter 17 »which is effective because the ΡΙΪΓ diode is high resistance, blocks the frequency F and at the output 18 only the frequency F / n occurs.

2. If the voltage source Jo is a DC voltage supplies, which is a few volts, and therefore corresponds to the logic "1", closes the series circuit of the capacitor 2o and the PIEF diode the capacitance diode 1 short and also the PIN diode 24 the bandpass filter 17. At the output only the frequency F occurs.

-12-

309818/0755

It will now be "described how the individual elements." work, in particular the capacitors 15 and 16.

If the voltage source 3o outputs the logical "0", i.e. the frequency E / n occurs at the output 18, then in order to achieve maximum efficiency it is necessary that the real part of the impedance at the output of the capacitance diode 1 has a defined value. Since the frequency F / n generally finds an ohmic load between terminal 18 and ground at the output it is favorable between the input of the bandpass filter 17 - which is assumed to be seen at the ohms Output resistance is adapted - and the line to provide an impedance converter, which in the embodiment as a capacitive impedance converter with the two capacitors 15 and 16 is formed. If you choose the capacitors 15 and 16, the an ^ - tap 9 for inductance 8 and the value of this inductance correct, you get one favorable impedance between the output of the capacitance diode 1 and ground ..,

If the voltage source 3o supplies the logical "1", i.e. the partial output 18 supplies the frequency F, then it is desirable that the arrangement of the parts 4-, 5 »7» 8, 15 and 16 the transmission of the frequency F from entrance to exit 18 not obstructed. Ideally, this arrangement would be a parallel resonant circuit with the resonance frequency F. However, one obtains

309818/075 5

a satisfactory result if one takes into account that different values are possible for the inductance 4 and the capacitance 5, the only condition to be observed is that the resonance frequency is F / n. When the divider to operate within a specific frequency range, allowing the variable capacitor ₅ 7 that can adjust the proper impedances at frequencies F and P / n.

FIG. 2 shows a further development of the basic circuit shown in rectangle I according to FIG. 1. Same Parts have the same reference numbers.

The capacitor 5 of FIG. 1 is connected in series a fixed capacitor 39a and an auxiliary capacitance diode 4oa replaced. The capacitance diode 4oa receives its gate voltage from a first variable DC voltage source 44a via a Filter, which is constructed similarly to the filter of the capacitance diode 1. It consists of a resistor 43a, a choke 41a and a decoupling capacitor 42a.

The capacitor 7 according to FIG. 1 is corresponding through the series connection of a fixed capacitor 39b and a second auxiliary capacitance diode 4ob replaced. The varactor diode 4ob receives its bias voltage from a second variable direct voltage source 44b via a filter, which consists of the Parts 43b, 41b and 42b consists'.

-14-

309818/07 $$

_ 14 -

The arrangement of Fig. 2 is very favorable when the frequency to be divided within a certain frequency band of. F - £ F and F + AF lies.

n ~~ η

The capacitor 39a and the capacitance diode 4oa can be chosen so that for the limit values the control voltage 44a of the series resonant circuit parts 4-, 39a and 4oa on the frequencies F-

and F + AF is coordinated. n ~

When using such a circuit, the bandpass filter 12 according to FIG. 1 can be omitted.

Correspondingly, the capacitor 39b and the capacitance diode 4ob are chosen so that for the limit values the control voltage 44b of the parallel resonant circuit consisting of capacitance diode 1, capacitor 39b, Capacitance diode 4ob, inductance 8 and the impedance, which is on line 1o and the tap 9 acts on the frequencies F -AF

and F + AF is coordinated. η

The voltage sources 44a and 44b are shown in FIG. 2 as separate voltage sources. These However, voltages can also be derived from a common primary voltage source. For example when the generator, which supplies the frequency F to the input 11, turns on itself is a voltage controlled oscillator working with a capacitance diode. In this case it can the DC voltage for this varactor as well

-15-309818 / 0755

for the voltage sources 44a and 44b derived from a single common voltage source are in such a way that the voltages are supplied by voltage dividers or that the Resistors 43a and 4-3Id are adjustable are.

If the high-frequency divider described here is used in a synthesizer, then is the only one Voltage source the output of the frequency comparison stage of the synthesizer.

4 claims

1 sheet. Drawings, 2 fig.

309818/0755

Claims (3)

Claims High-frequency divider, at the output of which either the input frequency or the input frequency divided by η (η integer ^> 1) can be removed, characterized in that a parametric oscillator (I) which oscillates on a subharmonic F / n of the input frequency F is provided, which consists of a parallel resonant circuit (7) 8) and a series connection of a capacitance diode (1) with a series resonance circuit (4,5) and to which the input frequency is fed as a pump frequency that parallel to the capacitance diode (1) of the oscillator (I ) there is a first switching element (21) which can be switched from a high-ohmic to a low-ohmic state and that the oscillation with the frequency F / n is tapped via a tap on the parallel resonant circuit inductance (8) and via a second switching element (24) , which can be actuated simultaneously with the first switching element (21), bypassable bandpass filter (17) is fed to the output (18). 2. Divider according to claim 1, characterized in that the first (21) and the second (24) switching element are PIN diodes. 309818/0755 3rd divisor after. Claim 1, characterized in that the oscillator (I) is preceded by a bandpass filter (12) ″ tuned to the frequency F. 4-. Divider according to one of the preceding claims, the input frequency F of which can be selected within a range F _Q ± ΔΙΓ, characterized in that a second capacitance diode ('4-ob) is connected in parallel with the resonant circuit _{capacitor (39 "b 5 Fig. 2),} whose capacitance is adjustable by a first DC control voltage (44b) and that in ßeihe with the capacitor (39a, Fig. 2) of the series resonant circuit, a third capacitance diode (4-oa) is connected, the capacitance of which is controlled by a second DC control voltage (4-4-a ) is adjustable. 30S83S / Ö755 Blank page