DE1081072B - Shortwave receiver - Google Patents

Description

GERMAN

The invention relates to a shortwave receiver which can be continuously tuned over several relatively wide shortwave ranges and which can also work with a spread spectrum to facilitate tuning at locations with a high density of stations (radio bands); In the case of spread spectrum tuning in the relatively narrow radio bands, the apparent resistances of the tuning means, which remain unchanged in the continuous tuning, are changed by relatively small amounts with the help of special fine tuning means. This has the same tuning accuracy is obtained for each of the to be spread broadcast bands, namely because the ratio of fine tune means to the tuning means of the steady oscillation circuit ¹ S remains unchanged the advantage.

If such a receiver can be tuned to several relatively wide shortwave ranges, the change of these shortwave ranges being carried out by switching over the invariable tuning means, the above-mentioned ratio to the fine tuning means is generally changed at the same time during this switchover. If the broadcast bands to be spread are distributed over the various broader shortwave ranges ^, the tuning accuracy in the individual bands is then no longer the same.

The invention has the purpose of avoiding this disadvantage and the consistent tuning accuracy at least approximately to restore.

According to the invention, when changing the relatively wide shortwave ranges, the Size or the control range of the special fine-tuning means for the purpose of adapting to the respective value the voting means, which remain unchanged in the continuous voting, have been changed.

A receiver was already known in which a spread spectrum was used in different radio bands was carried out, for which purpose a special set of variable capacitors for each of these bands was provided, which was switched on alternately when the relevant band was selected. The fine-tuning means are switched over, but not at the same time as in the invention with the change of broader shortwave ranges.

The invention is explained in more detail with reference to the drawing.

In the drawing, an oscillating circuit 1 is shown, which can be tuned in two short-wave ranges is and at the same time set up in each of these short wave ranges for spread spectrum reception is.

In the position shown, the oscillation circuit is controlled by a variable tuning capacitor Shortwave receiver

Applicant:

Philips Patentverwaltung GmbH,
Hamburg 1, Mönckebergstr. 7th

Requests after. Law No. 8 AHK are provided

and before the Arbitration Commission for Goods, Rights

and interests in Germany pending

Theodorus Antonius Spoor, Eindhoven (Netherlands), has been named as the inventor

Sator 2, a fixed self-induction coil 3 and a variable self-induction coil serving for band spreading 4 formed. Between the coils 3 and 4 are two mechanically coupled, connected in series Switches 5 and 6 switched. The mechanical coupling is shown schematically by a dotted line 7 shown.

When the two switches 5 and 6 are switched, the coil 3 is switched off and one smaller coil 8 connected in series with part of the variable self-induction coil 4. To this Purpose, a tap 9 is provided on the coil 4, which with a contact of the switch 6 in Connection.

The tap 9 is selected in such a way that the percentage change in the total inductance obtained with the coil 4 of the oscillating circuit 1 is approximately the same in the two positions of the switch.

The switches 5 and 6 can be part of the wavelength switch form, which is already available in the receiver for switching to the intermediate and long wave ranges.

Claims (4)

PATENT CLAIMS: 1. Shortwave receiver that can be continuously tuned over several relatively wide shortwave ranges is and is also provided with means for band spreading and for the waveband area circuit of the impedance, which remains unchanged with the constant coordination Resonant circuit part, is changed, characterized in that when changing the shortwave ranges • s 009 508/281 at the same time the size or the control range of the special fine-tuning means is changed in such a way that that the tuning accuracy is practically the same for all spread reception bands, 2. Shortwave receiver according to claim 1, characterized in that the at the steady Voting unchanged part of the resonant circuit is a fixed inductance and for band-spread tuning a variable inductance is used. 3. Shortwave receiver according to claim 2, characterized in that the fixed inductance and the variable inductance are connected in series. 4. Shortwave receiver according to claim 1, 2 or 3, characterized in that the fine-tuning means can be changed in their size or their control range by means of a switch with is mechanically coupled to the receiver's waveband switch. 1 sheet of drawings 009 508/281 4.60