DE2824295A1 - DEVICE FOR IMPROVING THE OUTPUT WAVEFORM OF A MANUALLY CONTROLLED PULSE GENERATOR FOR USE IN AN ELECTRONIC TUNING DEVICE WITH PRESET POSSIBILITY - Google Patents

Description

PATENT ADVOCATES A. GRÜNECKER

DiPL-INGl ■ *

H. KINKELDEY

[»-IMG.

W. STOCKMAlR

DR-INa-AeE (CALTECHt

K. SCHUMANN

DR RER NAT ■ DIPL.-FHYS.

P. H. JAKOB

OPL-ING.

G.BEZOLD

DR RERNAT · DfPL-CHEM.

8 MUNICH 22

MAXIMILIANSTRASSE 43

P 12 779

Means for enhancing the output waveform of a manually controllable pulse generator for use in an electronic tuning device with presetting

The invention relates to radio receivers for several wavebands, in particular to an electronic tuning device of the radio receiver, in which the wave ranges or frequency bands and the channels can be preset digitally.

Due to the recent developments in electronics, radio receivers have been improved in various ways. One of these improvements is disclosed in Japanese Utility Model No. 11353/1975. This utility model concerns one Multi-band receiver with pre-setting option that uses a voltage-dependent resistor (varactor diode) as a tuning element and has a control for this purpose. The controller includes a channel selection switch, one through the channel selection switch memory to be addressed, an up / down counter that is generated by a manually operated pulse generator or a channel signal which is set from the addressed memory location

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TELEPHONE (Ο8Θ) 233Ββ2 TELEX 05-90380 TELEGRAMS MONAPAT TELECOPER

2'8 2 A 2 9 5

is read out, and a digital / analog converter for converting an output signal of the counter into an analog signal which is fed to the variable capacitor (the varactor diode), since: in the radio receiver is provided. This arrangement forms a tuning circuit which is responsive to the analog signal for a To create tuning to a desired signal in the preset channel.

In this case the channel selection switch consists of several non-interlocking switches.

The up / down counter is determined by the output of the Memory always controlled when a channel selection signal is detected by one of the channel selection switch. For a multi-band receiver At least one frequency band selection switch can be provided which is in series with the channel selection switches is switched.

In this case, however, there are the output signal of the channel selection switch from that of the band selection switch in the standby state differs, all contacts of the channel selection switch in the shutdown state or low state during the Band selection switch is in the switched-on state with the exception of those times in which between adjacent frequency bands a band selection takes place. For this reason, the output signals of the two switches with the different Standby states at least two types of circuit arrangements are necessary.

Although this electronic tuner enables a relatively large amount of preset information to be reliably obtained can be specified, the channel section is relatively complicated because the memory stores the information. Down counter supplies in accordance with the output signal of the channel selection switch. In other words: if you go, for example Assumes that the channel is to be changed from channel number 3 in band A to channel number 3 in band B, that is, when changing from a channel in a first band to the corresponding

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If you want to change the channel of another band, it is necessary to turn the band selection switch from A to B again to operate the channel selection switch corresponding to the desired channel 3.

In order to provide the recipient with an improvement with regard to the above-mentioned disadvantages, a device according to Fig. 1 proposed.

In Fig. 1, a pulse generator 1 comprises a pair of output terminals; Voting pulses are sent manually on one of these output terminals generated, and clock pulses KC are generated on the other. The tuning pulses are either up counting pulses U or down counting pulses D, depending on the direction of manual operation of the generator. The output terminals of the Pulse generator 1 are connected to a binary up / down counter 2, which according to the clock pulses KC forward or counts down, depending on the forward or backward pulses of the pulse generator 1. Part of the output signal of the Up / down counter 2 is fed to a frequency indicator 3, which in this embodiment is a digital indicator is trained.

The frequency display 3 provides an indication of the selected frequency using a certain number of the most significant bits of the parallel counter output of the up / down counter 2. The output of the counter 2 is still fed to an input of a pulse synthesizer (synthesizer) 4, which accordingly the output of the up / down counter provides a serial pulse train which a predetermined number of Contains pulses corresponding to the output signal of the counter 2. An output of the pulse synthesizer 4 is fed to a low-pass filter 5 supplied. The low-pass filter 5 and the pulse synthesizer 4 form a digital / analog converter. A contact d a first Band selection switch 6 is connected to an output of the low-pass filter 5. The band selection switch 6 has three contacts a, b and c, which are connected to varactor diodes in tuning circuits for bands A, B, and C, respectively.

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A channel selection switch 7 comprises a plurality of non-locking switches 7a to 7e. One side of the switches 7a to 7e are commonly connected to a voltage source + V.

A second band selection switch 8 is mechanical with the band selection switch 6 coupled, and a contact arm d of the switch is with the common connection point of the switches 7a to 7e tied together-

A read / write memory (RAM) comprises a channel memory 19, the inputs of which are connected to the channel selection switches 7a to 7e are, an address decoder 20, the inputs of which with the outputs of the channel memory 19 and with the contacts a, b and c of the Band selection switch 8 are connected, as well as a RAM 21, the inputs of which are connected to the outputs of the address decoder 20. The RAM 21 stores the output signals of the switches in such a manner that, in response thereto, the output signal of the up / down counter 2 is stored in an assigned address of the RAM and read out therefrom and supplied to the memory 2.

A control circuit 10 has one input connected to one side of a preset switch 11, the other side to is connected to the common connection point of the channel selection switch 7 and the other band selection switch d. How it works of the control circuit 10 is such that it gives a load signal L to the counter 2 when the preset switch 11 is off and an output signal is supplied from one of the channel selection switches 7a to 7e. Furthermore, the Control circuit 10 outputs a write signal W to RAM 9, when the preset switch 11 is on. The control circuit 10 can be of various designs and includes a controller 12, a tape switch detector 14 and a load pulse generator 15. The controller 12 has an input with the Preset switch 11 and multiple inputs with the other sides the switches 7a to 7e are connected. For the tape switch detector, these inputs are connected to contacts a, b and c of the switch connected accordingly. The charging pulse generator has an input connected to the output of the tape switch detector 14.

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The controller 12 supplies a load signal and a write signal to the up / down counter or to the RAM 9.

If the pulse generator 1 is operated in one direction in order to generate up counting pulses U, these are fed to the up / down counter 2, with the result that the counter counts the pulses KC generated by the pulse generator 1. The parallel outputs of the counter 2 are connected to the stages of the pulse synthesizer 4 accordingly. The stages of the pulse synthesizer 4 can supply signals of different frequencies, which can be effected by frequency division of an oscillation signal by means of different dividers in accordance with the parallel output signals of the counter 2. The synthesizer 4 composes signals of different frequencies, which are generated by its stages, in accordance with the output signal of the up / down counter to generate a serial pulse train comprising a number of pulses corresponding to the output signal of the up / down counter. Counter s corresponds to. The serial pulse train from the pulse synthesizer 4 is fed to the low filter 5 in order to remove the high frequency component and ^{to generate a DC voltage signal 1} which corresponds to the output signal of the counter 2. The DC voltage signal is fed to a varactor diode in one of the tuning circuits (not shown) which has been selected by the band selection switch 6 in order to obtain a tuning at the corresponding frequency.

An appropriate number of the most significant bits of the output signal of the counter 2 is fed to the frequency indicator 3 in order to make the received frequency visible in a digital manner.

For the presetting it is assumed that in a desired Band a desired channel has been selected in the manner described above.

By turning on the switch 11 and then turning it on any one of the channel selection switches 7a to 7e is generated in the control circuit 10, a write signal W and the RAM 9 supplied so that the counter output of the forward Z reverse

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Counter 2, that is, a digital signal corresponding to the tuned received frequency, can be stored in an address of the RAM 9. This address is set by the tape selection switch 8 and a switched-on switch 7a to 7e assigned. In this way, certain channels can be in certain bands can be preset in the RAM. Such a preset channel in a certain band is selected by the contact of the band selection switch and the corresponding channel selection switch is selected. Since when selecting the band selection contact and the tape selection switch, the preset switch 11 is turned off the controller 10 supplies the band signal L to the up / down counter. As a result, the signal read out in parallel from the RAM 9 is supplied to the counter 2, the RAM 9 the output signals of the band selection switch 8 and the Channel selection switch 7 is received as a readout address.

The up / down counter 2 provides an output signal in the above, and this signal is supplied to the pulse synthesizer 4 as in the manual mode. Changing the channel in the same band can be accomplished by simply selecting a desired channel switch will.

Should only the band be changed, whereby the number of channels is retained is, it is sufficient to switch the corresponding contact of the band selection switch 8 to the desired band.

The pulse generator should be a device which has a simple structure and is easy to use. To meet these requirements, the pulse generator have a mechanical structure and comprise a turntable mounted on a shaft, the shaft having a free end has to which a button is attached. The disc includes several equidistant holes or slots around its circumference are distributed. At least one light-emitting element is provided on one side of the pane, and on the other side the disk is provided at least one light receiving element so that the emitted from the light emitting element

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Receive light from the light receiving element through the slits can be. By turning the knob in one direction or the other, the light receiving element becomes intermittent Light received, so that the light-receiving element delivers a series of pulses, the number of which corresponds to the angle of rotation of the disc. True, this is a pulse generator useful in some respects, however, the output pulse waveform of the light receiving element depends on the speed of rotation of the button and is not rectangular, but sinusoidal, which is the digital processing of the output pulses makes difficult. Although the number of output pulses should be large in order to receive a correspondingly large amount of information, it is also difficult to increase the number of slots due to the space constraints. Due to unfavorable Reflection and / or light scattering reduces the S / N ratio (S / N ratio), with the result that the channel selection becomes unstable.

It is an object of the present invention to provide the output waveform to improve the pulse generator.

Another object of the invention is to improve the waveform with a simple device which is integrated into an integrated circuit can be included.

Another object of the invention is to provide a test circuit for the device that can be easily incorporated into an integrated circuit can be included.

A preferred concept of the invention is to provide the output waveform a manually operated tuning pulse generator of an electronic tuning circuit with presetting possibility, when used in a multiband radio receiver varactor diodes will improve. A Schmitt trigger circuit is used here, which is equipped with a trigger level test circuit can be equipped, both arrangements can be included in one IC.

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In the following an embodiment of the invention is explained in more detail with reference to the drawing. Show it:

1 shows a schematic block diagram of the electronic tuning control circuit explained above with the possibility of presetting.

2 shows a manually controllable pulse generator according to the present invention Invention which can be used in the circuit of FIG.

Fig. 3 is a block diagram of a wave shaping device according to of the invention for insertion between the pulse generator and the up / down counter in Fig. 1, and

FIG. 4 shows a test circuit for the wave shaping device shown in FIG .

As seen in Fig. 2, there is a pair of light receiving elements 44 arranged on one side of a disk 42, slots 42 being formed on disk 42 evenly over its circumference are. A corresponding pair of light-emitting elements 45 are arranged on the other side of the disk 42, see above that the elements 45 can receive light from the light emitting elements through the slits 42a. It's two sets of Elements provided so that the direction of rotation of the disc can be detected in a simple manner. To see the waveform of the To improve the pulses received from light-receiving elements in order to facilitate their processing in the digital circuit, as is the case, for example, with rectangular pulses, the slot 42a is tapered.

Due to this taper, the light emitted from the light emitting element 45 is collimated and falls with sharp outlines on the light receiving element 44.

The disk 42 is carried by a shaft 61 on which a gear 75 is mounted. A gear 71 is on the shaft 61 and a gear 72 integrally formed therewith rotatably mounted as shown in the drawing. A gear 74, whose Tooth number is greater than that of gear 75, comes with the latter

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engaged. A gear 73 is formed integrally with the gear 74. The gear 73 meshes with the gear 72. The gear 71 meshes with a gear 52 which is fastened on a shaft 41. A button 51 is on one end the shaft 41 attached.

The gears 52, 71, 72, 73, 74 and 75 constitute an accelerating mechanism for increasing the number of obtained from the light receiving element 44 by turning the knob 51 manually Impulses.

With this' accelerating mechanism the number of output pulses without increasing the number of the slots is substantially increased, leading to an improvement in the output waveform. It is advisable to make each of the slits 42a in the disk 42 tapered so that the area of the light inlet side is slightly larger than that of the light outlet side. With this conical configuration of the slits, the light flowing through the slit is well collimated, and the output signal of the light-receiving elements is sharp-edged.

Although this affects the output waveform in the manner explained, will not always get a correct rectangular shape.

In order to further improve the waveform of the output pulses of the pulse generator, according to the invention is between the output terminals of the pulse generator 1 and the up / down counter 2, a Schmitt trigger circuit is connected, as can be seen from FIG. Obtained by using the Schmitt trigger circuits 80a and 80b the output pulses of the pulse generator 1 rectangular shape, which is best suited for digital processing.

The control circuit according to the invention can be designed as an integrated circuit. The one indicated by the dashed line in Fig. 1 indicated part can be designed as an integrated "circuit will. This means that the control device, with the exception of the pulse generator 1, the low-pass filter 5, of the frequency indicator 3, the band selection switches 6 and 8, the channel selection switch 7a

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to 7e and the preset switch 11 is suitable for the Training as an IC.

When designed as an integrated circuit, the arrangement of the Schmitt triggers 80a and 80b represents a further problem. That is, the trigger level of the Schmitt trigger circuits 80a and 80b must be checked at least when preparing the device will. In order to check the trigger level, it is necessary to have test terminals on the output sides of the Schmitt trigger circuits 80a and 80b to be provided.

Since the number of pins in an IC is limited, it is undesirable to use the IC pins for this purpose. Therefore, it is highly desirable to have the number needed to test the Schmitt trigger circuits 80a and 80b Minimize clamps.

Fig. 4 shows an embodiment of a test circuit which only one connector is required. The test circuit includes a pair of switching elements 81a and 81b such as N-channel MOS transistors with open drain. The transistor 81a has its drain electrode connected to a test terminal 90, the source electrode is grounded and the base electrode is connected to an output of the Schmitt trigger circuit 80a. The drain electrode of the transistor 81b is connected to the test terminal 90, the source electrode is grounded, and the The base is connected to the output of the Schmitt trigger 80b.

The Schmitt trigger circuits 80a and 80a are used in a known manner 80b to convert the essentially sinusoidal output wave of the pulse generator 1 at a given threshold value into a To convert impulse wave. It is therefore necessary to adapt the pulse generator 1.

When testing the Schmitt trigger circuits, the test terminal is connected to a positive terminal via a protective resistor (not shown) connected to an energy source. Then the voltage fed to an input of the Schmitt trigger 81a is gradually changed.

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changes. A change in the voltage at test terminal 90 due to the on / off function of the transistor 81a is checked. The voltage value fed to the Schmitt trigger 81a when the voltage at the test terminal changes is the threshold value The threshold value of the Schmitt trigger 80b is checked accordingly.

Even then, with this test circuit, only one terminal needs to be provided when the number of Schmitt trigger circuits is increased. Since the output signal of the test part continues through the switching element is received and is detected at the test terminal, there are no effects with regard to the input signal of the up / down counter 2. The source electrodes of the switching elements can be connected to another terminal of the IC be, for example, to a reset terminal of the same. In this case, the test terminal does not need to be provided because the reset terminal can also be used as a test terminal.

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Claims (2)

PATENT ADVOCATES A. GRÜNECKER DIPL.-INGL H. KlNKELDEY DR-ING. W. STOCKMAIR OQO / OQR «-.NG ^ ₁ CALTECH, / LQ L "! £ vJ« J κ. SCHUMANN OR BER NAT.-CHPL-PHYS P. H. JAKOB OfPL-ING. G. BEZOLD ORRERUOT-QPL-OEM. 8 MUNICH 22 MAXIMILIANSTRASSE 43 June 2, 1978 P 12 779 PIONEER ELECTRONIC CORPORATION No. 4-1, Meguro 1-chome, Meguro-ku, Tokyo, Japan Claims / 1.) ■ Electronic tuning device with presetting option, a manually operated pulse generator and an up / down counter, the inputs of which with at least two outputs of the pulse generator are connected, and means for enhancing the output waveforms of the pulse generator, characterized by one with one of the outputs of the pulse generator (1) connected first Schmitt trigger (80a) and one connected to the other output of the pulse generator (1) second Schmitt trigger (80b). 2. Device according to claim 1, characterized in that a threshold test arrangement (81a, 81b, 90) for testing the threshold level of the first and second Schmitt trigger is provided. ORIGINAL INSPECTED 809851/0772 TELEPHONE (OSS) 932883 TELEX OS-2O3BO TELEGRAMS MONAPAT TELECOPER Device according to Claim 2, characterized in that the threshold value test arrangement has a first switching element (81b) responsive to an output of the first Schmitt trigger (80a) to provide an output supply, which indicates the threshold value of the first Schmitt trigger (80a), and that an on an output signal of the second Schmitt trigger (80b) responsive second switching element (81a) is provided to an output signal supply, which indicates the threshold value of the second Schmitt trigger, and that the outputs of the first and second Switching element are interconnected. 809851/0772