AU759701B2

AU759701B2 - Radio receiver equipment

Info

Publication number: AU759701B2
Application number: AU10302/00A
Authority: AU
Inventors: Andreas Ritschen; Rainer Wittig
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1998-09-02
Filing date: 1999-09-01
Publication date: 2003-04-17
Anticipated expiration: 2019-09-01
Also published as: WO2000014872A1; DE19839857A1; DE59902289D1; EP1110317B1; JP2002524955A; EP1110317A1; AU1030200A

Description

-1- Radio Receiver Equipment The invention relates to a radio receiver device with a tuning stage tunable to a connected receiving antenna, a frequency converter stage with a mixer oscillator, which can be controlled by the tuning signal for the converting of the received high frequency signals to a defined intermediate frequency position and with further processing stages for the forming of an audible low frequency signal.

Radio receiver devices have been equipped with this principle construction for many years.

The respective tuning stage is so dimensioned that the tuning is enabled by means of the tuning signal over a possible receiving area. Correspondingly, the mixer oscillator of the frequency converter stage is tunable to convert the high frequency selected with the frequency converter stage to the intermediate frequency defined in the radio receiver device. Tuning stages are used for the achieving of good tuning properties, consisting of a first tunable tuned circuit, a multiplier stage and a second tunable tuned circuit.

As, in various countries, various band selections are enabled, for example for VHF reception, it is necessary to design the radio receiver devices as various types for the countries involved in order to enable an optimal adaptation of the used tuning level to the frequency band used in the respective country. This leads to the necessity of the storage S for separate radio receiver device types. In the case of car radios, the further disadvantage that if the car concerned spends time in another country, radio reception with the inbuilt radio, without its modification, is only partially possible or is no longer possible at all.

For example, the frequency band for VHF reception in the European countries lies between 87.5 and 108 MHz, whereas the comparable frequency band in Japan lies between 76 and MHz. It can be seen that a receiver intended for Europe can only receive a small edge V00. area of the frequency band used there.

0 30 The conceivable wider arrangement of the tuning stage to cover the entire possible frequency band between 76 and 108 MHz would be, at justifiable cost for the tuned circuit, only possible at the expense of the tuning characteristics of the tuning stage and therefore S cannot be considered.

cnot be considered.

18/02/03,ehl 1848.spc,l -2- The object of the invention is, therefore, to provide a radio receiver device of the type mentioned at the outset in such a way that the reception of the same types of radio signals, in particular VHF signals is possible in various bands with separate, generally overlapping band limits without loss of the tuning properties of the tuning stage.

According to the present invention there is provided a radio receiver device with at least two separately active, tunable tuning stages for two band selections connected to a receiving antenna with a switch for the optional connection of one of the tuning stages to a frequency converting stage with a mixer oscillator for the converting of received high frequency signals to a defined intermediate frequency, the mixer oscillator being convertible in its tuning range with a switch-over to one of the tuning stages in such a way that its oscillating frequency is set for a first band selection of the first band area of the first tuning stage around an intermediate frequency above the frequency to be received and for a second band area of the second tuning stage around the intermediate frequency below the frequency to be received.

According to the invention at least two parallel tuning units are connected to the receiving antenna, which are separately active-switchable and their outputs are connected with the common frequency converter stage and that the mixer oscillator is designed with a switchover is switchable to one of the tuning units in its tuning range.

The radio receiver device is therefore a multi-norm receiver device, which can receive in particular, VHF radio transmissions in bands with various band limits. For the bands concerned with the various band limits at least two parallel tuning units are planned, which are actively switched separately, so that a reverting to the other tuning unit can be prevented.

With the selection of the active tuning unit, a respective switching over of the mixer oscillator in the frequency converter stage is undertaken. To this end, the mixer o o o 18/02/03,ehl 1848.spc,2 WO 00/14872 PCT/DE99/02769 3 oscillator is provided with a tap, which for the purpose of the switch-over, can be switched to active or inactive.

The invention thus enables the operation of the radio receiver device in various countries in which various band limits for the reception of radio signals of a certain type, for example VHF radio signals are established. Of course, the invention can be used for various band limits in the medium wave, short wave or long wave ranges.

In a particularly advantageous embodiment of the invention, the receiving antenna can be switched to active via a coupling capacitor and a switch only for the tuning unit connected to the frequency converting stage via the switch-over. Each tuning unit not used is disconnected from the receiving antenna by means of the coupling capacitor, which can be connected to earth. Through the dimensioning of the coupling capacitor it can be ensured that the disconnected tuned circuit does not influence the closed tuned circuit.

In a preferred embodiment of the invention, the mixer oscillator is so constructed that its frequency can be adjusted for a band selection of a first tuning unit around the intermediate frequency below the receiving frequency and for a band selection of a second tuning unit around the intermediate frequency above the receiving frequency.

By means of this choice of frequency positions of the mixer oscillator, interference through the oscillator frequencies can be reduced.

The invention will be described in greater detail in the following on the basis of an embodiment represented in the drawing.

The drawing shows a schematic representation of the main tuning levels for the tuning stages of the invention.

"ki WO 00/14872 PCT/DE99/02769 4 In the embodiment of the invention two tuning units 2, 3 are parallel connected to a receiving antenna 1. The tuning units 2, 3 each have a coupling capacitor 21, 31, the ends of which not connected to the receiving antenna 1 being able to be connected, via a switch 22, 23 to earth. The connection point between coupling condensers 21, 31 and the switches 21, 31 is connected to a tuned circuit 23, 33 by means of a tuning signal VT. This output signal reaches a second tuning circuit 25, 35 by means of the tuning signal VT. The outputs of the two band passes are connected to two contacts of a switch 4 whose output contact forms an input of a frequency converting stage 5 as an integrated circuit. The frequency converting stage 5 features a mixer stage 51 on whose output the defined intermediate frequency ZF is set which, for the VHF reception represented here, is 10.7 MHz. A second input of the mixer stage 51 is provided with an oscillator signal, which is generated by an oscillator stage 52 integrated in the frequency converting stage 5 and an externally connected frequency determining oscillator circuit 6. The oscillator circuit 6 consists, as is customary, of an oscillator coil 7 with two part coils 71, 72 on the connection point of which a tapping 73 is provided, which can be applied parallel to the part coil 72 with a switch 74 to earth.

Parallel connected to the oscillator coil 7 is an oscillator capacitor 8, which consists, as is customarily the case, of two variable capacitance diodes 81, 82 connected antiparallel. The tuning voltage VT can be directed to the connection point of the two variable capacitance diodes 81, 82, by means of which the capacity of the capacitance diodes 81, 82 and thus the frequency of the oscillator 6 can be adjusted.

The tuning voltage VT is generated, as is customary, with the aid of a phase locked loop (PLL) in which the tuning signal VT can be controlled by means of a controllable frequency divider 54 to which the output signal of the oscillator at the output of the boosted oscillator stage is directed via a buffer amplifier 55. The setting of the frequency divider 54 is controlled as usual for the purpose of tuning by means of a microprocessor (not shown) via a control bus 56.

WO W00/14872 PCT/DE99/02769 The intermediate frequency signal ZF generated in the frequency converting stage is, as is known, further processed in the radio receiver device and is converted to a reproducible low frequency through a loudspeaker, headphones or similar.

The drawing shows the positions of the switches 22, 32, 4, 74 for the active switching of the first tuning unit 2. The receiving antenna 1 is, because of the opened switch 22, connected by means of the coupling capacitor 21 to the actively switched tuning unit 2, by means of which the bunching of the received signals in the tuning unit 2 is achieved. The closed switch 32 brings about the disconnection and uncoupling of the second tuning unit 3 from the receiver antenna 1.

A usual selective filtering takes place by means of the tuned circuits 23, 25, the medium frequency of the tuned circuits 23, 25 being set by the tuning signal VT. The receiving signal selected in this way reaches, over the switch 4 which is connected to the output of the second tuned circuit 25, the frequency converting stage 5 and is there directed to the mixer stage 51. At the second input of the mixing stage 51 the oscillator signal of the frequency-determined oscillating circuit 6 is directed over the boosting oscillator stage 52. At the oscillator circuit 6, because of the closed switch 74 the part coil 71 determining only the frequency and therefore the receiving area being active. Inside the mixing stage 51 the intermediate frequency signal is formed from these two signals, this signal serving the further processing stages of the formation of an audible low frequency signal.

In the embodiment represented, the first tuning unit 2 can be designed, for example, for the VHF band used in Europe between 87.5 and 108 MHz. Should the radio receiver device now be used, for example, in Japan, where the UHF band lies between 76 and 90 MHz, a switching of the second tuning unit to active of the second tuning unit 3 is undertaken. With respect to the representation in the drawing, the switches 22, 32, 4, 74 are switched in the other position respectively, so that the receiving antenna 1 is now uncoupled from the first tuning unit 2 by the coupling capacitor 21 and the closed switch 22 and the receiving signal is processed from the receiving IWO 00/14872 PCT/DE99/02769 6 antenna 1 via the coupling capacitor 31 in the second tuning unit 3. Regardless of the fact that this tuning unit 3 is designed for the desired frequency range, for example between 76 and 90 MHz, processing takes place in the same way as described above for the first tuning unit 2. The switch now connected to the output of the second tuning circuit 35 connects the second tuning unit 3 to the frequency converting stage The opened switch causes the complete coil 7 formed from the series connection of the two part windings 71, 72 in the oscillator circuit 6 to be active, resulting in the required frequency change.

For the forming of the tuning signal VT the now correct part relations are set via the control bus 56 on the frequency separator 54 by the microprocessor (not shown).

The switching of the oscillator circuit 6 is preferably so carried out that it can be tuned for the receiving range of the first tuning unit (87.5 to 108 MHz) between approximately 98 and 119 MHz in order to produce the intermediate frequency of 10.7 MHz. The frequency of the oscillator circuit 6 lies in this case, then, above the frequency of the signals received by the receiving antenna 1.

For the receiving band of the second receiver unit 3 (for example 76 to 90 MHz), the tuning frequency of the oscillator, on the other hand, lies preferably at 64 to 79 MHz, 10.7 MHz below the receiving frequency.

The embodiment described is intended for two different receiving bands. It is, of course, possible and appropriate to plan for three or more receiving bands a corresponding number of tuning units and, if applicable, a corresponding number of switch-overs of the oscillator circuit 6.

Claims

1. A radio receiver device with at least two separately active, tunable tuning stages for two band selections connected to a receiving antenna with a switch for the optional connection of one of the tuning stages to a frequency converting stage with a mixer oscillator for the converting of received high frequency signals to a defined intermediate frequency, the mixer oscillator being convertible in its tuning range with a switch-over to one of the tuning stages in such a way that its oscillating frequency is set for a first band selection of the first band area of the first tuning stage around an intermediate frequency above the frequency to be received and for a second band area of the second tuning stage around the intermediate frequency below the frequency to be received.

2. The radio receiver device according to Claim 1, wherein the mixer oscillator is formed with an oscillator coil provided with a tap and wherein the mixer oscillator can be switched, by means of a switching of the tap to active or inactive.

3. The radio receiver device according to Claim 1 or Claim 2, wherein the receiving antenna can be active switched via a coupling capacitor and a switch respectively only for the tuning units connected to the frequency converting stage.

4. The radio receiver device according to any one of the preceding claims, *wherein the tuning stages feature a first tunable tuned circuit, an amplifier stage and a second tunable tuned circuit. ooo. .:o.oi

5. The radio receiver device according to any one of the preceding claims, wherein the frequency converting stage features a mixer stage, an oscillator-amplifier stage, a buffer amplifier, a frequency divider programmable via a data bus and a PLL stage. S o oo o* 18/02/03,ehl 1848.spc,7 -8-

6. A radio receiver device, substantially as hereinbefore described with reference to the accompanying drawing. Dated this I 9th day of February, 2003-02-18 ROBERT BOSCH GMBH By Their Patent Attorneys CALLINAN LAWRIE I 8/02/03,ehl I 848.spc,8