KR100699310B1 - Multi-tuner receiver - Google Patents

Abstract

At the receiver, the two tuners TUN1, TUN2 allow to receive different signals simultaneously. The two tuners are integrated into one module (MOD). This may cause mutual interference. However, there are a variety of methods that are cost effective to offset this mutual interference. One such method is to ensure that the oscillation frequency of one of the two tuners does not coincide with either the radio frequency of the signal received by the other tuner or any sub harmonics of the radio frequency.

Description

Multi-tuner receiver {MULTI-TUNER RECEIVER}

The present invention relates to a receiver comprising at least two tuners for simultaneous reception of different signals. The invention also relates to a multimedia device and an add-on card comprising such a receiver.

The Philips Television (TV) set 37PW9761 type has two tuner modules to allow simultaneous display of two different TV programs. TV programs are broadcast at various respective radio frequencies in the range of 45 MHz to 860 MHz. Broadcast TV programs are fed to two tuner modules via a TV splitter in a TV set via a radio frequency inlet. Each of the two tuner modules has a shielded encasing with a mixer and an oscillator for converting radio frequencies to an intermediate frequency of 40 MHz. Each oscillator has adjustable oscillation frequencies. The oscillation frequency determines which radio frequency, and therefore which broadcast TV program, is to be converted to 40 MHz intermediate frequency for display and displayed. For example, if the oscillation frequency is 500 MHz, the TV program broadcasted at the 460 MHz radio frequency may be converted to a 40 MHz intermediate frequency and displayed as a result.

DE-3443859-A1 (Japanese Laid-Open Patent Publication No. 60-117927) discloses a receiver having frequency synthesis and two receiver systems. The first of the receiving systems changes its oscillation frequency within the frequency band in which the receiving frequency of the other receiver system occurs. The first of the receiver systems selects the desired receiving station with phase locked loop circuit and control circuit. The control circuit controls the channel selection of the first of the receiver systems to change its oscillation frequency so that the oscillation frequency does not occur in a frequency range that incorporates frequencies near the reception frequency of the receiver that is different from the reception frequency.

US Patent 5285284 A1 (Korean Patent No. 0103773) discloses a television receiver having a sub-picture tuner and a main-picture tuner. Both sub-picture tuners and main-picture tuners can select the received signal separately by changing the respective oscillation frequencies with channel select control signals. These varying oscillation frequencies are generated by the PLL frequency-synthesizer circuit. The PLL includes a programmable divider that divides the fixed reference oscillator frequency by a controllable number to obtain a selectable frequency of the oscillator signal. This oscillator signal is fed to the mixer and has the frequency required to receive a particular channel. If the sub-picture tuner picture is not displayed, the sub-picture tuner is still active. In order to prevent interference from the sub-picture tuner to the main-picture tuner, the oscillation frequency of the sub-picture tuner is set to a fixed frequency higher than the highest frequency of the channels to be received by the main-picture tuner.

EP-0595314-A1 discloses a broadcast receiver comprising a first audio tuner for receiving a broadcast channel to be audible in a loudspeaker, and a second audio-tuner for checking the signal quality of the same broadcast on other channels. . The second tuner does not disturb the first tuner by preventing the local oscillation frequency of the second tuner from occurring in frequency bands in which the first tuner may be disturbed.

1 is a block diagram illustrating the basic principles of the present invention.

2-7 illustrate additional features that may optionally be used to effect the invention.

8 is a block diagram of an example of a receiver in accordance with the present invention.

9 illustrates an example of a multimedia device according to the present invention.

The present invention seeks to provide a receiver of the type mentioned above that allows for a more cost effective implementation, especially with respect to the background art. Claim 1 defines a receiver according to the invention. Claims 9 to 12 each define a receiving method, a multimedia device, an add-on card, and a single shielded case, all in accordance with the present invention. Additional features that may optionally be used advantageously in practicing the invention are defined in the dependent claims.

The present invention contemplates the following aspects. To date, the need for receivers capable of receiving different signals simultaneously has been relatively low. For example, out of the total number of TV sets sold, only relatively small percentages have two tuners that provide picture-in-picture (PIP) functionality, for example. The reason for this is that at present, it is cost effective to implement PIP TV by the conventional method. That is, two separate tuner modules are used that are applicable separately in many other types of TV sets, and which are relatively mass produced and relatively inexpensive.

However, the situation may be different in the future. The amount of information and entertainment available to consumers is growing rapidly. It also increases the number of ways information or entertainment is provided, for example transmitted in analog or digital form, via satellite, cable TV networks, telephone networks, and the like. In addition, multimedia tends to concentrate various types of information such as text, data, audio, and visual information. In view of the above, the need for receivers capable of receiving different signals simultaneously can increase to a level where solutions different from the background art solutions can be more cost effective.

According to the invention, two or more tuners are included in one module. If two or more tuners are included, the various components are shared by two or more tuners such as, for example, liquid crystals, integrated circuits, printed wiring boards, metal products, connectors, and pin blocks. Can be. The costs to be saved when the various components are shared may exceed the costs associated with including two or more tuners in one module if the demand for the type of receivers under discussion is high enough.

DETAILED DESCRIPTION OF THE INVENTION The present invention and additional features that may optionally be used to practice the invention advantageously will become apparent from the following description with reference to the drawings.

First, some descriptions of the use of reference signs appear. Similar items will be represented by the same letter codes throughout the drawings. In one figure, various similar items may be shown. In that case, numbers will be added to the character code to distinguish these items from each other. In addition, if an item forms part of a higher-order item, it will indicate that the numbers of all reference signs belong to higher order items with the same number of reference signs. In the description and claims, any numerals of reference signs may be omitted as deemed appropriate.

1 illustrates the basic principle of the present invention. In FIG. 1, at least two tuners TUN1, TUN2 are integrated into one module MOD. Although FIG. 1 shows two tuners TUN1, TUN2, other tuners may be included in the same module MOD.

2 shows each of two tuners TUN1, TUN2 with an oscillator OSC connected to a mixer MIX that converts a signal from radio frequency to an intermediate frequency. 2 also shows the following additional features. Each oscillator of the two tuners, oscillation frequency Fosc1 or Fosc2, does not match any sub-harmonic of the radio frequency of the signal received by the radio frequency (RF2 or RF1) or each other tuner. Has This is preferably applied substantially through the respective tuning ranges of the two tuners TUN1, TUN2.

The feature of FIG. 2 is based on the following considerations. Two tuners TUN1 and TUN2 integrated in one module may interfere with each other. In particular, the oscillator of one of the two tuners may interfere with the signal received by the other tuner. The oscillator signal can be propagated to various parts of the receiver in a number of different ways. For example, it can be propagated through induction in metal parts, or by crosstalk to printed circuit board tracks carrying switching signals and variable capacitor voltages, for example. The attenuation of the overall propagation experienced by the oscillator signal is often very unpredictable and may also change significantly as a function of frequency. This is important because the oscillator signal contains harmonic frequency components as well as fundamental frequency components. Thus, the amplitude of the harmonic frequency component may be higher than that of the fundamental frequency component in certain portions of the receiver.

There are several ways to counteract the above mutual interference. One method may allow the oscillator signals to be maintained at sufficiently low levels. However, decreasing the oscillator signal level will generally degrade performance in terms of noise and frequency stability.

Another method can cause the oscillators to be electromagnetically shielded. However, shielding is relatively expensive and in some cases is not effective. The following example is given as an explanation. For TV reception, an interference distance of at least 60 dB is desirable. Assuming that the level of the TV signal received by the tuner is 1 mV, this is a typical value and the level of the interfering signal will not exceed 1 dB. Assuming the level of the oscillator signal of the other tuner is 1V, this is a typical value and requires 120dB of attenuation between the two tuners. If two tuners are integrated into one module, any internal shielding to provide this attenuation, even if practicable, will be expensive and difficult to design.

Another method may block the reception of radio frequency combinations in which the two tuners TUN1 and TUN2 interfere with each other. This can be done, for example, by a suitably programmed computer which controls the two tuners TUN1, TUN2. However, since harmonic frequency components of the oscillator signals also need to be considered, it may be necessary to block the reception of relatively many radio frequency combinations. In such a case, end users will receive several signals that are relatively suppressed that can be received simultaneously.

If the features of Figure 2 are applied, the fundamental or harmonic frequency components of the oscillator signal of either of the two tuners (TUN1 or TUN2) directly interfere with the signal received by each of the other tuners (TUN2 or TUN1). I will not. Thus, oscillators OSC1 and OSC2 are allowed to operate at signal levels that provide satisfactory performance in terms of noise and stability. In addition, this does not require any relatively accurate shielding and does not require the reception of relatively many radio frequency combinations. Thus, the features of FIG. 2, respectively or in combination, contribute to the quality and versatility of reception and cost-efficiency.

The feature of FIG. 2 will provide additional advantages when the splitter is used to apply signals from the common terminal to the two tuners TUN1, TUN2. In such a case, the splitter does not need to provide high attenuation between the two tuners TUN1 and TUN2 to prevent mutual interference. Thus, the splitter can be realized with relatively few active components, or can be realized without any active components. Active components consume power and cause noise and distortion. Thus, the features of FIG. 2 allow for a relatively power efficient, noise free and distortion free splitter. It should be noted that these advantages may be obtained if the two tuners are separated as in the prior art.

3A shows the following additional features. The oscillation frequency Fosc1 of tuner TUN1 exceeds the highest possible radio frequency RFmax2 that tuner TUN2 can receive. This is preferably applied substantially through the tuning range of tuner TUN1.

The feature of FIG. 3A is based on the following considerations. If the tuner TUN1 needs to be able to tune in a relatively wide tuning range, the matching of the radio frequency RF2 or the sub-harmonics of the radio frequency RF2 of the signal received by the tuner TUN2 coincides with the oscillation frequency Fosc1. It will be difficult to avoid. Relatively complex and therefore expensive methods may be necessary to avoid such a match. However, if the features of FIG. 3A are applied, any such agreement will of course be excluded. Thus, the feature of FIG. 3A contributes to cost efficiency, especially when the tuner TUN1 needs to be tuned through a relatively wide tuning range.

3B illustrates the following additional features. The oscillation frequency Fosc1 or Fosc2 in each of the two tuners exceeds the highest possible radio frequency RFmax2 or RFmax1 that the other tuner can each receive. The feature of FIG. 3B is effective in conjunction with the feature of FIG. 3A. The oscillation frequency Fosc2 at the tuner TUN2 also exceeds the highest possible radio frequency RFmax1 that the tuner TUN1 can receive. Thus, the feature of FIG. 3B contributes to the cost efficiency, especially when both tuners TUN1 TUN2 need to be tuned through a relatively wide tuning range.

The following descriptions of the features of FIGS. 3A and 3B appear. When the features of FIG. 3A are applied, tuner TUN1 may be ready to receive a low radio frequency signal and at the same time tuner TUN2 may be prepared to receive a high radio frequency signal. Further, if the oscillation frequency Fosc2 of the tuner TUN2 is located higher than the radio frequency RF2 of the signal received by this tuner, then the radio frequency RF1 of the signal received by the tuner TUN1 is changed. Will definitely exceed. As a result, the oscillation frequency Fosc1 or Fosc2 at each of the two tuners will exceed the radio frequency RF2 or RF1 respectively received by the other tuner. Also, neither the fundamental components of the oscillating signals nor any harmonic components can interfere with the received signals. Thus, the feature of FIG. 3A can provide advantages similar to that of FIG. 3B.

Nevertheless, the features of FIG. 3B may be preferable to those of FIG. 3A for the following reasons. Assuming that both signals S (X) and S (Y) are received at the same time, signal S (Y) will have a higher radio frequency than signal S (X). The received signal S (Y) needs to be discontinuous for another signal S (Z) having a radio frequency lower than S (X). The following takes place in the case of FIG. 3A with the provision as described above. Tuner TUN2 takes over the reception of signal S (X) from tuner TUN1, and the signal will be maintained. This take-over is necessary in view of the high-low radio frequency relationship. The takeover may be a cause of interruption in the reception of the signal S (X). On the contrary, however, no handover is required when applying the features of FIG. 3B. Thus, the features of FIG. 3B allow uninterrupted reception even if any concurrent reception changes.

4 shows the following additional features. The difference ΔFosc between the oscillation frequencies Fosc1 and Fosc2 of the two tuners TUN1 and TUN2 exceeds the intermediate frequency bandwidth BWIF. This applies preferably through substantially tuning ranges of the two tuners TUN1, TUN2.

The feature of FIG. 4 is based on the following considerations. Oscillators OSC1 and OSC2 may be phase modulated with each other as a result of being electromagnetically connected to each other. This will cause the oscillator signal to have sidebands. 4 shows sidebands Fsb + 1 and Fsb-1 belonging to oscillator OSC1 and sidebands Fsb + 2 and Fsb-2 belonging to oscillator OSC2. The sidebands are located at + ΔFosc and -ΔFosc from the oscillation frequencies Fosc1 and Fosc2. The sidebands of each oscillator signal will be mixed with each received signal. As a result, the received signal converted into respective intermediate frequencies will also have sidebands located at + ΔFosc and -ΔFosc from these respective intermediate frequencies.

If the features of FIG. 4 are applied, these sidebands will not interfere directly with each received signal. Thus, the feature of FIG. 4 cancels the mutual interference between the two tuners TUN1, TUN2, which may occur as a result of the mutual electromagnetic coupling of the oscillators. Thus, there will be a relatively small need to offset this mutual electromagnetic connection with methods, such as providing an internal shielding or improving the quality (Q) of the oscillator tank circuit. These methods are relatively expensive, especially at relatively high frequencies. Therefore, the features of FIG. 4 contribute in terms of cost efficiency.

The following additional descriptions of the features of FIG. 4 appear. Sidebands Fsb + and Fsb− may cause intermodulation products that can compromise reception. However, each sideband typically has such a small amplitude that in many cases this type of mutual interference can be ignored. Also, the amplitude of each sideband Fsb +, Fsb− will decrease as the difference ΔFosc between the oscillator frequencies Fosc1, Fosc2 increases.

When one of the two tuners TUN1, TUN2 operates in an autosearch mode, it is advantageous to skip, for example, by means of software, the frequency range in which cross-phase modulation can occur. In that regard it should be noted that any harmonics of the oscillation frequencies Fosc1, Fosc2 do not substantially contribute to any interphase modulation of the oscillators OSC1, OSC2. Thus, if one of the oscillator frequencies (Fosc1 or Fosc2) is relatively close to the harmonics of the other oscillator frequency (Fosc2 or Fosc1), mutual phase modulation will rarely or completely occur. Thus, if the frequency ranges of the oscillators OSC1, OSC2 do not overlap, no skipping during automatic search will be necessary.

5A shows the following additional features. The frequency divider DIV1 is connected between the oscillator OSC1 and the mixer MIX1 in the tuner TUN1. Before describing some of the advantages of this feature, the following should be noted. The frequency divider DIV1 produces subharmonics of the oscillator signal. In principle, the sub harmonics can interfere with the signal received by the tuner TUN2 (not shown in FIG. 5A). Thus, the divider DIV1 and any circuit that connects it to the mixer MIX1 should be recognized as potentially interfering with the transmitters. However, with a suitable design, these potentially interfering transmitters will be significantly weaker than the potentially interfering transmitters in which oscillator OSC1 is present when the present invention is not used. Thus, the features of FIG. 5A do not represent a method of integrating two tuners in a manner not possible in the prior art.

Advantages of the features of FIG. 5A will be described with reference to FIG. 5B. 5B is a frequency diagram showing a radio frequency RF1, an oscillation frequency Fosc1, and a mixed frequency Fmix1. The mixing frequency Fmix1 is an oscillation frequency Fosc1 divided by N1, and N1 is a division factor of the frequency divider DIV1. FIG. 5B also shows the intermediate frequency IF1 which is the difference between the mixing frequency Fmix1 and the radio frequency RF1.

Assuming that the intermediate frequency IF1 preferably has some desired value, for example a value of 40 MHz for TV reception, the advantages of the features of FIG. 5A are as follows. As described above, the oscillation frequency Fosc1, such as mutual interference between the two tuners TUN1, TUN2, is allowed to counteract the appropriate selection of the division factor N1 of the frequency divider DIV1. In addition, if a frequency divider is also connected between oscillator OSC2 and mixer MIX2 in tuner TUN2, as will all be shown in FIG. 1, this will provide a large number of possibilities against mutual interference. . The dispensing factor of the latter dispenser, by itself, leads to a wider degree of freedom in achieving it.

The following additional descriptions of the features of FIG. 5A appear. The features of FIG. 5A are not essential to the invention and are not essential to the other features described. The oscillation frequency Fosc1 shown in FIG. 5B can be applied directly to the mixer MIX1 without any frequency division. However, in that case, the intermediate frequency is the difference between the oscillation frequency Fosc and radio frequency RF1. Thus, the intermediate frequency will be higher. Circuitry for processing relatively high intermediate frequency signals is relatively expensive, power consumed, and / or important. Thus, because the features of FIG. 5A allow relatively low intermediate frequencies, this provides for cost efficiency, energy efficiency, and strength.

6 shows the following additional features. The division factor N1 of the frequency divider DIV1 illustrated in FIG. 5A may be adjusted. 6 shows R2, R3, R4, R6, respectively obtained by division factors N1 = 2, 3, 4, 6, 8, 12, 16, when oscillator OSC1 can be tuned between 1000 and 2000 MHz. The various mixed frequency ranges of R8, R12, R16 are shown. Thus, if the frequency divider DIV1 can be adjusted to have one of these divide factors, it allows mixing of frequencies through the range of 62.5 MHz to 1000 MHz. However, when the division factor N1 is fixed, the oscillator OSC1 becomes tunable over a wide range, allowing a similar selection of mixing frequencies. This makes it more difficult or nearly impossible to realize oscillator OSC1. As a solution, several tunable oscillators may be used, in which each tunable oscillator is responsible for a portion of the range of mixed frequencies. This solution is common to TVs where oscillators are used in each of the VHF-low, VHF-high, and UHF bands. However, the features of FIG. 6 only allow tuning through a relatively wide frequency range with a single oscillator that needs to be tuned through a relatively narrow frequency range. Thus, the features of FIG. 6 contribute in terms of cost efficiency.

Figure 6 also shows the following advantageous additional features. Between a substantial portion of the range of mixed frequencies, ie, 83.33 MHz to 666.67 MHz, there is one or more oscillator frequencies from which a constant mixed frequency can be obtained. In other words, select oscillator frequencies for a constant mixed frequency. This selection allows the oscillator frequency Fosc1 of tuner TUN1 to be removed relatively much from the oscillator frequency Fosc2 of tuner TUN2, thus canceling out mutual interference. This is not important if the oscillators OSC1, OSC2 operate in respective frequency ranges that overlap. Properly selected division factor N1 ensures that oscillators OSC1 and OSC2 are not too close to each other in frequency. In addition, if an adjustable frequency divider is connected between the oscillator OSC2 of the tuner TUN2 and the mixer MIX2, there will be a much larger choice for keeping the oscillator frequencies Fosc1 and Fosc2 away. Appropriate software can be used to select the optimal dispensing factor or dispensing factors in any given case.

In Fig. 6, there are two frequency ranges where there is no selection of oscillation frequency, i. Although it is advantageous for a selection to exist within these frequency ranges, the absence of selection will not induce significant mutual interference in most cases. First of all, the two tuners generally do not need to receive simultaneously at the same or almost the same radio frequency, in which case the respective oscillating frequencies Fosc1 and Fosc2 coincide or nearly coincide. In addition, it will be difficult for two adjacent radio frequency channels to be occupied by available signals, so there are very few changes that require simultaneous reception on two adjacent radio frequency channels. In other cases where such reception is required, the oscillation frequencies Fosc1 and Fosc2 will be spaced by a distance N times the distance between two adjacent radio frequency channels, where N is the frequency division factor of the dividers DIV1 and DIV2. Is the same as Thus, as the oscillation frequencies Fosc1 and Fosc2 are divided, they will be spaced relatively broadly, and even if the same division factor is used, any sidebands will be outside of the intermediate frequency band as a result of interphase modulation. .

7 shows the following additional features. Mixer MIX1 and frequency divider DIV1 form part of integrated circuit MOIC1. Therefore, the circuit carrying the sub harmonics Fosc1 N1 of the oscillation signal is small in size. As a result, any radiation of the sub harmonics Fosc1 N1, which may potentially interfere with the signal received by the tuner TUN2, will be relatively moderate. Thus, the feature of FIG. 7 improves the degree to which two tuners TUN1 and TUN2 are integrated.

The following additional descriptions of the features of FIG. 7 appear. First, mixer MIX1 is preferably implemented in the form of a stable circuit. This provides inherent suppression of any oscillator subharmonics present at the input and output ports of mixer circuit MIX1. Preferably, divider DIV1 is also implemented in the form of a stable circuit. Next, it should be noted that the integrated circuit MOIC1 may include other circuits. The dotted lines in FIG. 7 show that oscillator OSC1 may be included in whole or in part in integrated circuit MOIC1. If the tuner TUN2 also includes a frequency divider connected between the mixer MIX2 and the oscillator OSC2, these circuits may also form part of the integrated circuit MOIC1. As another example, integrated circuit MOIC1 may also include a phase-lock loop circuit.

8 shows an example of a receiver according to the invention, including the additional features of FIGS. 2 to 7. The receiver of FIG. 8 is a dual TV / FM receiver capable of simultaneously receiving two different TV broadcasts, or two different FM radio broadcasts, or a TV broadcast and an FM radio broadcast. To this end, two tuners for simultaneously converting two different radio frequency signals (Si1) (RF) and Si2 (RF) into intermediate frequency signals So1 (IF1) and So2 (IF2) respectively. TUN1, TUN2). Any radio frequency signals Si1 (RF) and Si2 (RF) may be TV broadcasts or FM radio broadcasts received at radio frequency inlets I (TV) and I (FM), respectively.

In FIG. 8, each of the two tuners TUN1, TUN2 includes a switch SW, three radio frequency input circuits RFIL, RFIM, RFIH, and an integrated circuit MOIC. Radio frequency input circuits (RFIL, RFIM, RFIH) are respectively arranged for the processing of signals in the VHF-low band, VHF-high band, and UHF band. Each of the integrated circuits MOIC includes a mixer MIX, a divider DIV, and an amplifier portion AMP of an oscillator OSC. Resonator portion RES of oscillator OSC is external to integrated circuit MOIC. Each of the integrated circuits MOIC also includes a phase locked loop circuit PLL and a digital analog conversion circuit DAC. Two tuners TUN1 and TUN2 share a crystal oscillator XTL that resonates at a reference frequency Fref with the memory circuit MEM.

Each of the two tuners TUN1 and TUN2 operates as follows. The switch SW is set to the TV position or the FM position, depending on whether it wants to receive a TV broadcast or an FM-radio broadcast. In the former case, the radio frequency signal Si (RF) may be processed in one of three radio frequency input circuits (RFIL, RFIM or RFIH). In the latter case, the radio frequency signal Si (RF) is processed by the radio frequency input circuit (RFIL) for the VHF-low band. The associated radio frequency input circuit, in all cases, supplies the properly processed radio frequency signal Sp (RF) to the mixer MIX of the integrated circuit MOIC.

Radio frequency input circuits RFIL, RFIM, and RFIH include tunable band pass filters, not shown, for simplicity. Tuning voltages VT for controlling the tunable band pass filters are obtained as follows. The control data CON containing information of the desired radio frequency effectively selects which tuning data TD is read from the memory MEM and supplied to the digital-to-analog converter circuit DAC. The selected tuning data TD causes the digital analog conversion circuit DAC to provide the tuning voltages VT such that the relevant radio frequency input circuits process the desired radio frequency signal Si (RF) in an appropriate manner. . Thus, with the appropriate tuning data stored in the memory MEM, the band pass filters can be sufficiently tuned through the VHF-low, VHF-high and UHF bands. Aberrations of tuning of the band pass filters with respect to each other can be reduced by manual adjustment.

The mixer MIX of the integrated circuit MOIC effectively multiplies the properly processed radio frequency signal Sp (RF) by the mixed signal Smix having the mixed frequency Fmix. In principle, the mixed frequency may be the sum or difference of the radio frequency of the desired broadcast and the desired intermediate frequency. For the receiver of FIG. 8, the mixing frequency is sum. The desired intermediate frequency is 40 MHz for FM radio reception and 10.7 MHz for TV reception. For example, if you want to receive a TV broadcast with a 210 MHz radio frequency, the mixed frequency would be 250 MHz. As another example, if one wants to receive an FM radio broadcast with a radio frequency of 89.3 MHz, the mixed frequency would be 100 MHz.

The mixed signal Smix having the mixed frequency Fmix is obtained as follows. The oscillator OSC provides an oscillation signal Sosc with an oscillation frequency Fosc that can vary between 1000 MHz and 2000 MHz. The oscillation frequency Fosc is controlled by the phase locked loop circuit PLL based on the control data CON and based on the reference frequency Fref which is 4 MHz, for example. The frequency divider DIV divides the oscillation signal Sosc with an adjustable frequency division factor N to obtain a mixed signal Smix. The adjustable dispensing factor (N) can be one of the following values: 2, 3, 4, 6, 8, 12, or 16. Thus, the frequency diagram of FIG. 6 applies to both tuners TUN1 and TUN2 of the receiver of FIG. For example, there are three choices for setting the mixing frequency to 250 MHz. The first is Fosc = 1000 MHz and N = 4, the second is Fosc = 1500 MHz and N = 6, and the third is Fosc = 2000 MHz and N = 8.

The following descriptions of the receiver of FIG. 8 appear. The relationship between the oscillation frequency Fosc and the band pass filter center frequencies of the radio frequency input circuits RFIL, RFIM, RFIH is not defined. For example, if one wants to receive a TV broadcast with a radio frequency of 210 MHz, the band pass filters of the associated radio frequency input circuit will be tuned to the radio frequency, but the oscillation frequency will be one of 1000 MHz, 1500 MHz, or 2000 MHz. If the tuning voltages VT are derived from the tuning voltage applied to the oscillator OSC, then the division factor N has to be taken into account, which makes it more complicated and therefore expensive. Thus, the way in which the tuning voltages VT are generated in the receiver of FIG. 8 is relatively cost effective.

Singapore patent applications 9600125.5, 9600123.5, and 9600124.3 (Dealer's Classification Numbers PHN15647, PHN15648, and PHN15649, respectively) describe features that may optionally be used to implement the advantages of the receiver of FIG. The aforementioned applications are incorporated herein by reference and the corresponding applications.

9 shows an example of a multimedia device according to the present invention. The multimedia device of FIG. 9 includes a box BOX and an image display device PDD. The box BOX has various data processing circuits, not shown, and has two tuners TUN1 and TUN2 and an add-on card AOC located in a single shielded case SSE. The two tuners TUN1, TUN2 comprise radio frequency inlets I (TV) and I (FM) for receiving TV broadcasts and FM radio broadcasts respectively. Two tuners TUN1 and TUN2 may be implemented, for example, as shown in FIG. 8. The two tuners TUN1, TUN2, for example, allow simultaneous display of two different TV broadcasts P1 and P2. The software for controlling the two tuners TUN1, TUN2 may be loaded into any type of memory constituting part of the multimedia device. Such software can be used, for example, to select an appropriate frequency division factor for any frequency divider (DIV) included in any of the two tuners TUN1, TUN2 as shown in FIG. 8.

The drawings and the above description illustrate rather than limit the invention. Indeed, various alternatives fall within the scope of the appended claims. The following conclusion may be drawn from this point of view.

There are several ways to physically spread the functions or functional elements across the various units. The drawings merely illustrate and illustrate one embodiment of the present invention very schematically. In addition, the present invention may be practiced through hardware that includes several individual elements and, at least in part, by a suitably programmed computer.

The invention can be used with great advantage in multimedia devices, but applications in other types of devices are not excluded. In addition, the present invention can be used with great advantage in, for example, TV sets, video tape recorders (VCRs), TV / VCR combinations. The present invention may allow such a device with features such as, for example, PIP, Split Screen, and Separate Teletext.

Although TV and FM radio reception have been exemplified, other types of reception are not excluded. The present invention can also be used, for example, for receiving wideband datacasts.

Examples of two integrated tuners are given, but two or more tuners can be integrated into one module. In the latter case, it is desirable that there is a greater choice in oscillation frequencies than in the case shown in FIG. This can be done, for example, by providing different dispensing factors, increasing the oscillation frequency range, or both.

Dispensing factors, such as 2, 4, 8, 16 and 3, 6, 12, respectively, are given as examples, not binary or binary, but a few dispensing factors such as 1.5 may also be used. In the latter case, the filter is preferably connected between the dispenser and the mixer. Fractional dividers generally provide signals with relatively asymmetric duty cycles. As a result, mixer performance may be degraded in terms of noise and signal handling. The filter will reduce any asymmetry in duty cycles and at the same time attenuate this degradation.

In the claims in which they arise, reference signs in parentheses shall not be construed as limiting.

Claims (7)

A receiver comprising a first tuner (TUN1) and a second tuner (TUN2) for simultaneously receiving different signals, The first tuner TUN1 is a first oscillator OSC1 connected to the first mixer MIX1 for converting a first signal at a radio frequency Sp1 (RF) into a first intermediate frequency So1 (IF). The second tuner TUN2 has a second oscillator connected to the second mixer MIX2 to convert the second signal at the radio frequency Sp2 (RF) into the second intermediate frequency So2 (IF). (OSC2), the first oscillator (OSC1) is an oscillation frequency that does not match the radio frequency (RF2) of the signal received by the second tuner (TUN2) or any sub-harmonics of the radio frequency (Fosc1), the second oscillator (OSC2) is oscillating frequency (Fosc2) that does not match the radio frequency (RF1) of the signal received by the tuner (TUN1) or any sub-harmonics of the radio frequency The first tuner has a first oscillator signal Fosc1 of the first oscillator OSC1 that varies in a certain range. In the receiver having a first phase locked loop (PLL1) for controlling the first oscillator (OSC1) in accordance with the control data (CON) further in order to obtain, The first tuner is adjustable to enable overlapping frequency ranges of the first mixed signal Smix1 to be supplied to the first mixer MIX1 such that there is one or more first oscillator signals from which a specific mixing frequency can be obtained. And a frequency divider DIV1 for dividing the first oscillator signal Fosc by a frequency division factor N1, The division factor N1 is selected to prevent the frequencies of the first oscillator and the second oscillator from getting too close together, thereby countering mutual interference between the first tuner and the second tuner. . The receiver of claim 1, wherein the second tuner (TUN2) further comprises another adjustable frequency divider (DIV2) connected between the second oscillator (OSC2) and the second mixer (MIX2). The receiver of claim 1, wherein the first tuner (TUN1) and the second tuner (TUN2) are integrated into one module (MOD). A method of simultaneously receiving different signals by at least a first tuner TUN1 and a second tuner TUN2, wherein the first tuner TUN1 receives a first signal at a radio frequency Sp1 (RF). It has a first oscillator OSC1 connected to the first mixer MIX1 for conversion to the intermediate frequency So1 (IF), and the second tuner TUN2 has a second signal at the radio frequency Sp2 (RF). Has a second oscillator (OSC2) connected to a second mixer (MIX2) to convert to a second intermediate frequency (So2 (IF)), the first oscillator (OSC1) is received by the second tuner (TUN2) The oscillation frequency Fosc1 does not match the radio frequency RF2 of the signal or any sub-harmonics of the radio frequency, and the second oscillator OSC2 receives the signal received by the tuner TUN1. Oscillation frequency (Fosc2) that does not coincide with the radio frequency of RF1 or any sub-harmonic of Has, the method according to the receiving method comprising the step (PLL1) for controlling the first oscillator (OSC1) in accordance with the control data (CON) to obtain a first oscillator signal (Fosc1) varying in a range, The method provides an adjustable frequency division factor that enables overlapping frequency ranges of the first mixed signal Smix1 to be supplied to the first mixer MIX1 such that there is one or more first oscillator signals from which a specific mixing frequency can be obtained. Dividing the first oscillator signal Fosc1 by N1) (DIV1), The division factor N1 is selected to prevent the frequencies of the first oscillator and the second oscillator from getting too close together, thereby countering mutual interference between the first tuner and the second tuner. Way. A multimedia device comprising the receiver of claim 1. An add-on card (AOC) suitable for forming part of a multimedia device, the add-on card comprising the receiver of claim 1. A single shielded encasing (SSE) comprising the receiver of claim 1.