FI66269C - FREQUENCY REQUIREMENT FOR ENTRY INTO RADIO FREQUENCY - Google Patents

Description

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Petent and Register AmBkan titledeeh MiJkrifkwt puMmratf 31.05.8 ^ (32) (33) (31) Requested msoHms · —Begird prtoritet 14.1 1.75 USA (US) 632060 (71) RCA Corporation, 30 Rockefeller Plaza, New York, NY 10022, USA (lb) (72) John Goodchilde Norie Henderson, Princeton, New Jersey, USA (US) (7 * 0 Oy Kolster Ab (5 * 0 Device for tuning a receiver to a radio frequency carrier -Anordning för avstämning av en mottagare av en radiofrekvent bärväg The present invention relates to an apparatus for tuning a receiver to a radio frequency carrier associated with a particular tuning station and having either a standard frequency or a non-standard frequency arbitrarily close to the standard frequency, the apparatus including an adjusted oscillator section for generating a local oscillator signal. and a mixer section for combining the radio frequency carrier and the local oscillator signal to generate an intermediate frequency signal having at least one data carrier having a standard value at a frequency.

In the United States, the carrier frequencies for wireless television broadcasts are allocated to VHF (very high frequency) and UHF (ultra high frequency) channels by the Federal Communications Commission (FCC). During such broadcast-type transmission, such frequencies must be maintained with high accuracy.

Recently, frequency synthesizers have been proposed that include a phase locked loop (PLL) to accurately generate local oscillator signals at specific frequencies corresponding to the various channels that the viewer may select. For example, using a tuning apparatus, a phase-locked loop is described in Digital Integrated Circuits Application Note ICAN-6716, entitled "Low-Power Digital Frequency Synthesizer Utilizing COS / MOS IC's" by R.E. Funk, published in 1972 RCA Solid State Databook is a COS / MOS Digital Integrated Circuits (SSD-203) published by RCA Corporation.

Other types of tuning a television receiver to standard frequencies are also known. In one type described in U.S. Patent No. 3,818,363, entitled "Automatic Tuning Equipment with Two Frequency Sweeping Components," invented by Sakamoto, issued June 18, 1974, the system includes two oscillators that are swept alternately and stepwise over a range of e-siters. on the broadcasting channel. By calculating the number of times the sweep and oscillator stop occur, it is possible to determine when the predictive local oscillator control voltage is close to but slightly less than the control voltage that is correct to tune that channel. The auxiliary sweep circuit then increases the control voltage to the correct tuning voltage.

A tuning apparatus of the frequency synthesizer type for standard frequency broadcasting carriers is thus known. However, not all television signals are transmitted on standard broadcast-type carriers. In certain television distribution systems, such as apartment buildings and hotel installations, television signals are connected to receivers via cables. In these and other systems that use cable (or even microwave links), the modulated broadcast carrier may be demodulated and then re-modulated on a different carrier that is randomly close to the standard broadcast carrier before it is connected to the receiver. As a result, it is desirable to provide apparatus for tuning receivers to such aberrant carriers.

An apparatus will now be described which can be used to tune a television receiver to both standard frequency carriers associated with conventional VHF and UHF channels and to non-standard frequency carriers arbitrarily located close to standard frequency carriers. This device according to the invention is characterized by an adjustable calculator which calculates, depending on the local oscillator signal and / or the stable frequency signal, to provide a predetermined relative frequency ratio between the local oscillator signal and the stable frequency signal, a first control device to adjust the frequency of the local oscillator signal according to said predetermined relative frequency ratio, a calculator control device coupled to the adjustable calculator for determining an adjustable coefficient indicating a frequency to set apart its nominal an amount within a predetermined range, which limits are determined by the non-standard frequency and the expected deviation of the standard frequency, and then to adjust the frequency of the local oscillator signal to reduce the deviation between the carrier frequency and the standard value.

The accompanying drawings show:

Figure 1 shows in block diagram form a channel tuning apparatus made in accordance with the present invention and used in television receivers.

Figure 2 shows a logic diagram for implementing a certain part of the tuning apparatus shown in Figure 1.

Fig. 3 shows partly schematically and partly in the form of a logic diagram embodiments for other parts of the tuning apparatus shown in Fig. 1.

Figures 4 and 5 show graphical representations of voltage-frequency characteristics with respect to parts of the tuning apparatus shown in Figure 1.

Figure 6 shows a table useful in understanding the operation of the tuning apparatus shown in Figure 1.

Figure 1 shows a general arrangement of a television receiver using a channel tuning apparatus made in accordance with the present invention. Radio frequencies (RF) are received at antenna 12 and amplified by radio frequency amplifier 14. The amplified RF signals are coupled to mixer 16, where they are combined with a local oscillator signal having a suitable frequency and provided according to the selected channel, as will be described later to form an intermediate frequency (vt) signal. . These vt signals are amplified by an vt amplifier 18 and then coupled to a video detector 20. The video detector 20 provides video signals including, for example, chrominance, luminance, and clock signal components from these amplified vt signals. The video signals are coupled to a video processing unit 22 which includes, for example, channels for processing the chrominance, luminance and clock signal components of this video signal to form an image on the picture tube 24.

The general arrangement described so far may use those components used in a CTC-68 type color television receiver, as shown, for example, in RCA color television service bulletin FILE 1974 C-5, published by RCA Corporation, Indianapolis, Indiana, USA

In the illustrated apparatus, the viewer enters channel selection information via the channel selection keypad 26. The keypad 26 includes, for example, a calculator type keypad with which VHF or UHF channels can be selected in decimal format. For example, the keyboard 26 may include a matrix circuit for converting decimal information to binary coded decimal (BCD) format. The binary coded signals representing the channel information are coupled to the channel number memory 28 along a multi-wire path 30.

Memory 28 converts the binary channel selection information into other binary signals representing the number "N" corresponding to the currently selected channel. For this purpose, the memory 28 may, for example, contain a read only memory (ROM) in which the "N" number information is stored for later use as a result of the input of binary signals from the keyboard 26.

The binary signals representing the number N are coupled along a multi-wire path 32 to a programmable frequency divider 34 arranged to divide the frequency of the incoming signals by the number N. The divider device 34 is arranged to switch a phase locked loop (PLL) a reference oscillator 40, a programmable "R" divider 38, a phase detector 36, and a low pass filter amplifier 46. The arrangement of this phase-locked loop in combination with the channel selection equipment forms a frequency synthesizer of the type described in the above-mentioned RCA Application Note and suitable for tuning a television receiver to standard frequency carriers.

Most of the rest of the block diagram shown in Figure 1 is directed to equipment that automatically tunes the receiver to carriers of a different frequency, such as may occur in central antenna television and similar (CATV and MATV) systems. A more detailed logic and block diagram for such an apparatus is shown in Figures 2 and 3. However, the description of the embodiment shown in Figures 2 and 3 is not given in detail, as such an application will be understood by one skilled in the art from the receiver tuning apparatus of Figure 1 below. For this purpose, parts of the embodiment shown in Figures 2 and 3 and the connections between them are denoted by the same reference numerals as in Figure 1. Also in order to align the embodiments of Figures 2 and 3 with reference to Figure 1, the following description of Figure 1 will refer to logical "O" and "1" signals. apply to control signals associated with this tuning apparatus. These logic "O" and "1" signals correspond to voltages close to ground and approximately +12 VDC, respectively, in the logic circuits of Figures 2 and 3, which may, for example, be formed from COS / MOS integrated circuits in which such voltages are used.

The tuning apparatus of the television receiver of Figure 1 operates in two modes. In its first, non-sweeping mode of operation, it wants to say that in order to receive a standard frequency carrier assigned to a selected channel, a programmable number N divider 34 and a programmable number R divider 38 are set to predetermined values, respectively.

When operating in the non-sweep mode used to tune the receiver to standard frequency carriers, the sweep mode switch 54 used by the viewer is placed in the open position (as shown) to bring the switch logic unit 56 to the ENABLE PYYt 1 "representing the ALLOW SWEEP control signal, i.e. complement) via line 58 and introduced into the computation preselection logic unit 62 via line 60 so as to deactivate the hardware associated with receiving the exception standard carriers as described below.

As a result of this ALLOW SWEEP control signal, the logic unit 56 generates a stop 1 control signal (logic state "O") which is connected to the clock unit 68 via line 90 to prevent clock pulses from coming from divider 66 and reaching the clock input (on line 114) and a countdown counter 42. As a result, the counter 42 does not change the divider number R of the divider device 38, as it does with the sweep mode, which will be described later.

In either mode, the viewer selects a channel by pressing or otherwise activating the appropriate keys on the channel selection keypad 26. The channel number memory 28 receives binary signals representing channel selection information from the keypad 26 and receives from its memory binary signals representing the number N corresponding to the selected channel. Binary information representing the number N is input to a programmable number N divider 34 so that it divides the frequency of the incoming signals by a number N.

In addition to taking binary signals from memory representing the number N when a new channel was selected in the non-sweep or sweep mode, the channel number memory 28 also generates a START PULSE control signal (logic state "1") which is connected to the switch logic unit 56 and 5614 (shown in Figure 3) and the operation of which will be described later. As a result of said START PULSE control signal, the switch logic unit 56 generates a control signal (logic state "O" in conductor 88) that causes the synthesizer / AFT switch 48 to switch the u output (lead 122) from the low pass filter and amplifier unit 46 the structure described above.

The START PULSE control signal is also connected to the calculation preselection logic unit 62 to reset it before entering new information 7 66269 from the channel number memory 28.

Channel number memory 28, in addition to generating an α-number to N programmable divider 34 and generating a START PULSE control signal, also provides three area switching control signals (logic modes "1") which are UHF control signals when the channel is in UHF area (e.g. channels 14). - 83), LOV control signal when the channel is selected from the lower VHF range (e.g. channels 2-6) and HIV control signal when the channel is selected from the upper VHF range (e.g. channels 7-13). The operating signals of the operating range switching together with the ENABLE SCAN OPERATION control signal are combined with the calculation preselection logic 62, as a result of which it selects the relevant number R.

These operating band switch control signals are also coupled in a suitable known manner (not shown) to voltage controlled tuning components, such as varactor diodes, in a VCO section 50 and a K divider 52 so as to adjust the frequency of the input signal by N in divider 34 according to the selected frequency band. the channel has.

The values of N and R for tuning the receiver to standard frequency carriers are shown in the table rows labeled "N" and "R does not sweep" in the columns of the table of Figure 6. The values in this table correspond to an embodiment in which the frequency of the crystal oscillator 40 is 5 MHz and the pre-divider 52 divides the frequency of the output signal from the voltage controlled oscillator 50 (VCO) by 256. It can be seen that the values of N are equal to the frequencies in megahertz when mixed with the corresponding received standard frequency carriers to generate a frequency difference for vt signals having an image carrier frequency of 45.75 MHz (a standard sized vt image carrier in most U.S. receivers).

Initially, when the viewer has selected a channel and a divider 34 with a programmable number N and a divider 38 with a programmable number R is activated, the VCO 50 oscillates at an arbitrary frequency (e.g., at a band selected at some point in the range). The operating frequency of the VCO 50 is converted based on the DC control signals from the low pass filter and the amplifier unit 46 until the error indicating output signal provided by the phase detector 36 indicates no phase or frequency difference between the output signals 34 and the programmable o-alga. At this time, a phase locked loop corresponding to a VCO section 50, a K divider 52, a programmable N divider 34, a phase detector 36, a programmable R divider 38, a crystal oscillator 40, and a low pass filter and amplifier unit 46 generates a local oscillator signal at the output of the VCO 50, the frequency fLQ of which depends on the frequency fxosc in the output signal of the crystal oscillator 40 according to the following expression f = NKf rLO R ^ OSC '1}

It should be noted that the output signal of the low pass filter amplifier unit 46 should be sufficient in its amplitude range to allow the local oscillator signal to vary in a certain frequency band for a given range beyond the central distance of adjacent channels and most preferably large enough to allow receiver tuning for all channels in that band. Thus, for example, in the lower VHF range, the sub-pass filter and amplifier unit 46 may provide control voltages in the range between a certain two different voltages sufficient to tune the receiver to any of channels 2, 3, 4, 5, or 6.

The output signal of the local oscillator VCO from section 50 is coupled to mixer 16, where it is coupled in a conventional manner to the output signal of RF amplifier 14 to form an vt signal including an image carrier at a frequency (e.g. 45.75 MHz) equal to the difference between received carrier and local oscillator signal frequencies. . The vt signal of this is amplified using the vt amplifier 18, and video information is output therefrom using the video detector 20. The video signals are processed by the signal processing unit 22 to form an image on the surface of the picture tube 24.

When the viewer chooses to receive signals from a different frequency carrier distribution system (e.g., using a central antenna or wide area antenna cable system), switch 54 enabling the sweep mode is placed in its closed position, 9 66269 which thus develops the to another, the sweeping mode of action. In this second, i.e., scanning mode, during reception of an anomalous frequency carrier that is arbitrarily close (e.g., in the range + _ 2 MHz) to the associated standard frequency carrier frequency, a programmable number divider 34 is reactivated at a fixed number corresponding to the selected channel. However, R divides 38 by initially setting the divider ratio to a numerical value less than the divisor ratio, i.e., the value corresponding to the associated standard frequency carrier (to which the programmable number R divider 38 would be set during the first mode), and then gradually incrementing it toward the second ratio. is greater than that corresponding to the associated standard frequency carrier until excitation is achieved or until another value is reached as will be discussed in more detail below.

When operating in sweep mode (as well as non-sweep mode), the viewer selects a channel by pressing down the appropriate keys on the channel selection keypad 26 and as a result binary information representing the number N is input to the programmable number N on the divider 34. 1 "), which is connected to the switch logic unit 56 to reset the flip-flops 5612 and 5614 to zero. As a result of the START PULSE control signal, the switch logic unit 56 generates a control signal (logic state "0" in line 88) that initially causes the synthesizer / AFT switch 48 to connect the output of the low pass filter and amplifier unit 46 to the control switch terminal of the VCO portion 50. In addition, the START PULSE control signal also returns the calculation preselection logic unit 56 before entering new information from the channel number memory 28. When operating in non-sweep mode, the channel number memory 28 also generates either a UHF, LOV or HIV control signal depending on the selected frequency band.

Based on either the HIV or LOV control signals generated by the channel number memory 28 and the ALLOW SWEEP control signal generated by the switch 54, the calculation preselection logic unit 52 66269 logic unit 52 combines the binary signals up and down with the counter 42 representing the first preselected value below which its value is the number R would be set for the same channel if selected during the non-sweep mode. The first preselected values corresponding to the different channels that have to be up and down during the sweep mode of operation by the counter 42 are indicated in the "START R" column in the table of Figure 6.

The computation preselection logic unit 62 also generates the complements HIV and LOV of the HIV and LOV control signals. These complement signals are coupled to the sweep stop logic unit 70 along the multi-wire path 64, bringing it to one of two preselected values (depending on whether the selected channel is in the upper or lower VHP range) above the numeric value at which the number R would be set in non-sweep mode. The second preselected value corresponds to the largest number to which the number R could be added during the sweep mode. Another preselected value corresponding to the different channels is indicated in the "END R" column in the table of Figure 6.

As a result of the ENABLE SWEEP control signal, the switching logic unit 56 generates an END SWEEP control signal (logic state "1" indicating the end of SWEEP ΦΦ 1 control signal at the input of the downlink 42) and allows the clock signal at As a result of these clock signals, the up and down counter 42 increments the number R from its first preselected value toward the second preselected value. Another preselected value corresponding to the different channels is indicated in the "END R" column in the table of Figure 6.

In operation, a phase-locked loop consisting of a VCO section 50, a K preselector 52, a programmable N divider 34, a phase detector 36, a crystal oscillator 40, a programmable R divider 38, and a low pass filter and amplifier unit 46 operates in the same way as the sweep mode f ^ Q in the local oscillator signal according to Equation 1 above. However, as each successive clock pulse from the output of the clock signal at divider 66 reaches up and down counter 42, R is incremented by a preselected number 66269 as indicated in the "<3R" column in the table of Figure 6, and R increments for different channels when the number A is chosen to be equal to 2, are also 2. As a result, the frequency of the local oscillator signal decreases (i.e., decreases gradually). The frequencies of the start and stop of the local oscillator signals and the frequency step sizes for the different channels are indicated in the "fLQALKU", "f ^ END" and "" columns for implementation in the table of Figure 6 when the number A is selected to be 2.

The output signal of the local oscillator VCO from section 50 is combined as well as the non-sweeping mode with the output signal of RF amplifier 14 in mixer 16 to provide a modulated vt signal whose carrier frequency is increased directly as a dependent domain corresponding to the frequency range in the local oscillator signal. The sweep range for each channel is selected to be wide enough to include the required local oscillator signal when combined with the received off-frequency carrier in mixer 16 to provide a modulated vt signal having an image carrier at a predetermined frequency, e.g., 45.75 MHz.

As the vt carrier is reduced, an automatic fine tuning (AFT) frequency discriminator unit 92 connected to the vt amplifier 18 generates a voltage that depends on the frequency deviation between the vt carrier frequency and 45.75 MHz. Fig. 4 is a graphical representation of the S-shaped voltage-frequency dependence as a characteristic curve 412 associated with an AFT circuit 92 having typical voltage and frequency values for the embodiment shown in Figs. 2 and 3. It can be seen that the S-shaped characteristic curve 412 has an amplitude range between a certain minimum and maximum amplitude, corresponding to a frequency deviation (+ 25 kHz) which is a fraction of the frequency gap between the channels (6 MHz). The direction in which the frequency of the modulated vt carrier is swept is shown in Figure 4.

The output signal generated at the output switch terminal indicated by the sign (+) of the AFT circuit 92 is connected via a conductor 104 to a threshold detector 82 where it is monitored. The threshold detector 82 generates a THRESHOLD control signal (logic state "1") when the voltage at the output (+) switch terminal AFT circuit 92 rises above a certain predetermined threshold value 414. This THRESHOLD control signal 66269 li is connected to the switch logic unit 56 via a wire 106 where it turns on the flip-flop 5612 of the switch logic unit 56.

An AFT amplifier 94 amplifies the AFT signal generated at the (-) switch terminal in the AFT circuit 92 and is connected there along a conductor 124. The amplifier factor of this AFT amplifier is selected so that the amplified AFT signal has substantially the same amplitude range between a certain first and second voltages as there is an output signal from the low pass filter and amplifier unit 46. This means that the amplitude range of the amplified output signal from AFT amplifier 94 should provide substantially the same voltage. combined with the VCO portion 50 than is also the output signal of the low pass filter and amplifier unit 46. It can be seen that the two different voltages of the amplified AFT signal correspond to the frequency deviations in the intermediate frequency carrier between the deviations associated with the maximum and minimum voltages on the frequency discriminator characteristic associated with the ATF circuit 92.

A graphical representation of the voltage-frequency characteristic 512 in the amplified AFT output signal from the AFT amplifier 94 is shown in Figure 5, which has typical voltage-frequency values for the embodiment shown in Figures 2 and 3. The direction of the frequency sweep of the modulated vt carrier is also shown. Also shown are approximate levels for the control voltages applied to the VCO section 50 corresponding to the channels in the lower VHF frequency range. It should be understood that similar characteristic dependencies are also associated with channels in the upper VHF region. Figure 5 also shows a partial graphical representation of a step-shaped waveform 514 similar to the output signal from the low-pass filter and amplifier unit 46, which increases the frequency of the modulated vt carrier.

The comparator 84 compares the output signal from the low pass filter and the amplifier unit 46 (waveform 514) connected there along the conductor 100, comparing it with the output signal AFT from the amplifier 94 (waveform 512) connected there via the conductor 98 and generates a COMPARISON control signal 1 "logic" are equal to each other. The COMPARISON control signal is coupled to the switch logic unit 56 via wire 102 and turns the switch logic unit 56 onto flip-flop 5614.

13 66269

When flip-flop 5612 is turned on as a result of the THRESHOLD control signal and flip-flop 5614 is turned on as a result of the COMPARISON control signal, the switch logic unit 56 generates a control signal (logic state "1" in line 88) disconnecting the output-input terminal The amplified AFT signal then adjusts the output frequency of the local oscillator signal from the VCO section 50.

If the frequency of the local oscillator signal shifts due to temperature changes, component value changes, or the like from the frequency obtained when the control input-input signal VCO to section 50 was connected from the output signal of the low-pass filter and amplifier unit 46 to the amplified AFT signal signal which resists the frequency change caused by the shift.

THRESHOLD control signal indicates that the amplified AFT signal changes in the right direction, causing AFT adjustment. The threshold 414 in Fig. 4 corresponds to the threshold 516 in Fig. 5. If the switch 48 connects the amplified AFT signals from this AFT circuit 92 directly to the VCO portion 50 before the amplified AFT reached the threshold 516, the AFT control would not be reached because the control voltage applied to the VCO portion 50 would change in the wrong direction. the portion 518 in the characteristic curve 512 instead of changing along the inclined portion 520.

The COMPARISON control signal indicates that the amplified AFT signal generates a control voltage which, when coupled to the VCO section 50, causes the VCO section 50 to generate a local oscillator signal having a frequency close enough to the frequency of the local oscillator signal associated with the selected channel. For example, assuming that channel 4 is the selected channel in question, if switch 48 is connected to connect the output switch terminal AFT amplifier 94 to the control input of VCO section 50 when the amplified AFT signal voltage is at 516, the control voltage applied to VCO section 50 would correspond to channel 2 instead of it would correspond to the control voltage required for channel 4.

Thus, the control of the VCO section 50 is switched from the phase locked loop control to the AFT control when both the THRESHOLD and REFERENCE control signals are on. In addition, when the THRESHOLD and COMPARISON control signals have already been provided, the switch logic unit 56 STOP SCAN 1 controls a control signal (logic state "0" on line 90) to prevent clock signals from entering the clock input at the clock input in the up and down counter 42 38 and to terminate the sweep operation as a result.

If no AFT control is implemented before the number R reaches its final value ("END R" in the table of Figure 6), a sweep stop logic unit 70 is generated. END SCAN ίψ 2 stopping the sweep. At this point, the viewer will see a poor quality picture and may select another channel or start a new scan interval by first selecting a new channel and then re-selecting the channel already initially selected.

It can now be seen that the frequency of the modulated IF carrier is shifted by decreasing the frequency of the local oscillator signal. This is desirable so that the first carrier to be reached is the desired picture carrier instead of the audio channel of the adjacent channel. This avoids or minimizes incorrect tuning.

It should be noted that if a UHF control signal has been generated by the channel number memory 28, even if the sweep-enabled switch 54 is closed to allow tuning of the receiver to aberrant carriers, the switch logic unit A in the up and down counting counter 42 via the clock on-off unit 68. As a result, the number R in the programmable number R in the splitter 38 does not increase when the UHF channel is selected, whether the switch enabling the sweep mode is depressed or not. This arrangement has been implemented because most television distribution systems do not re-convert UHF carrier frequencies for distribution on other UHF frequencies, and as a result, a sweep mode is not required when selecting a UHF channel. However, it should be noted that the tuning equipment can also be converted to scan UHF carriers with different frequency frequencies.

Although no detailed explanatory description of the embodiments shown in Figs. 2 and 3 has been given for the reasons already mentioned, with respect to the logic embodiment shown in Figures 2 and 3, the CD4027 integrated circuit included in the programmable R divider 38 is a flip-flop, which divides the frequency of the u-output signal of the CD4059 calculator of this integrated circuit, the latter also being included in the divider 38, dividing it by 2. As a result, the numbers set in the CD4029 integrated calculator forming the up and down counter 42 are only half of the corresponding R values shown in the table of Figure 6. In addition, only binary signals representing states "1", "2" and "4" to form the most significant number (MSD) of the numbers corresponding to the number of tens, and to form the least significant number (LSD) corresponding to the number of ones corresponding to "END R the numbers are combined with the wash end logic unit 70 because the MSD and the LSD in the numbers corresponding to the aforementioned "END R" do not need the number "8" to form them. In addition, binary signals for generating hundreds of numbers from the numbers provided by the up and down counter 42 are not connected to the sweep termination logic unit 70 because the number in the hundreds number is the same for and not added to both the lower VHF and upper VHF ranges.

Although, with reference to Figure 1, the addition of modulating vt carrier is accomplished by decreasing the programmable number R divider 38, it should be noted that alternatively the vt carrier frequency can also be reduced by decreasing the value of the number input to the programmable number N divider 34, as indicated by multicore 126, connected between a divider 34 programmable by the number N of the up and down counter 42. Moreover, although the tuning apparatus of Figure 1 has been described as reducing the frequency of the vt carrier in order to avoid tuning the receiver to the audio carrier of an adjacent channel, it should be noted that the frequency of the vt carrier can also be increased.

Claims (8)

16 66269 An apparatus for tuning a receiver to a radio frequency carrier associated with a particular tuning station and having either a standard frequency or a non-standard frequency arbitrarily close to the standard frequency, the apparatus including an adjusted oscillator portion (50) for generating a local oscillator signal and a relatively stable frequency signal; (16) for combining a radio frequency carrier and a local oscillator signal to generate an intermediate frequency signal having at least one data carrier having a standard value, characterized by an adjustable calculator (34, 38) that calculates from a local oscillator signal and / or a constant frequency to provide a certain relative frequency ratio between the local oscillator signal and the stable frequency signal, from a first control device (36, 46) connected in an adjustable manner; between the counter and the adjusted oscillator section for adjusting the frequency of the local oscillator signal according to said predetermined relative frequency ratio, a counter control device (42, 66, 68) connected to the adjustable calculator for determining an adjustable factor indicating the frequency the adjustable factor has a nominal value associated with the standard frequency of the radio frequency carrier and a second control device (62, 56) for setting the adjustable factor apart from its nominal value by a predetermined amount determined by the non-standard frequency and the expected frequency deviation of the standard frequency; to adjust the frequency to reduce the deviation between the frequencies of the carrier carrying the data and the standard value. Device according to claim 1, characterized in that the first control device (36, 46) generates a first control signal for adjusting the frequency of the local oscillator signal, the second control device has a discriminator (92, 94) for generating a second control signal representing and that the second control device has a switch (48) for coupling the first control signal to the first adjusted oscillator section (50) and for connecting the second control signal to the subsequently adjusted oscillator section. Device according to claim 2, characterized in that the discrainer (92, 94) has a predetermined frequency control range and that the switch (48) switches the second control signal to the adjusted oscillator part when the deviation between the frequencies of the carrier and the standard value is predetermined. within the frequency control range. Device according to claim 3, characterized in that the control device (42, 66, 68) of the calculator depends on predetermined states of the second control signal to change the adjustable coefficient to reduce the deviation between the frequencies of the carrier carrying the data and the standard value. Device according to claim 4, characterized in that the adjustable calculator has first (34) and second (38) programmable counters, the first programmable calculator being connected between the adjusted oscillator part (50) and the first control device (36, 46) for frequency division in the first an adjustable coefficient for generating a frequency-divided local oscillator signal, and every second programmable calculator is connected between the stable frequency signal source (40) and the first control device to divide the frequency of the stable frequency signal by the second adjustable coefficient; to generate a control signal depending on the frequency deviation of the frequency-divided local oscillator signal and the reference frequency signal. Device according to claim 5, characterized in that the first programmable calculator (34) depends on predetermined states of the second control signal. Device according to claim 5, characterized in that the second programmable calculator (38) is dependent on predetermined states of the second control signal. Device according to Claim 1, characterized in that the second control device (62, 56) initially moves the adjustable factor away from the nominal value, so that the frequency of the carrier carrying the data is shifted to a value higher than the standard value. 18 66269