GB2255436A

GB2255436A - Audio recording apparatus

Info

Publication number: GB2255436A
Application number: GB9206144A
Authority: GB
Inventors: Yeong-Jae Kim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1991-04-30
Filing date: 1992-03-20
Publication date: 1992-11-04
Also published as: DE4208739A1; JPH0581768A; GB9206144D0; KR920020459A

Description

212 5 5 4 3 c) AUDIO RECORDING APPARATUS The present invention relates to

audio recording apparatus.

A recording/reproducing system generally records and/or reproduces video and/or audio signals. Typical types include a video cassette recorder (hereinafter referred to as VCR), a video camera combining a VCR and camera, and an audio set. A recording/reproducing system can properly control audio according to low, middle and high frequency bands to suit the user, using a graphic equalizer during reproduction. The recording/reproducing system does not adopt a graphic equalizer in the recording operation. Therefore, in audio reproduction equipment which does not include a graphic equalizer, the selective setting of audio frequency bands according to a user's tastes has been impossible.

Preferred embodiments of the present invention aim to provide an audio recording apparatus for controlling the increase and decrease of amplitude according to frequency bands to suit the user, using a graphic equalizer in the recording of audio signal.

According to one aspect of the present invention, there is provided an audio recording apparatus in a recording/reproducing system for recording and reproducing a video and an audio signal, the apparatus comprising:

selecting means for selecting at least one signal from a plurality of audio signals input during recording; gain control means for increasing or decreasing the gain of an audio signal selected in said selecting means according to predetermined frequency bands; and audio signal recording means for recording on a recording medium an audio signal regulated in said gain control means.

Preferably, said gain control means includes at least one band-pass filter separated according to said predetermined frequency bands.

Preferably, said gain control means controls the increase or decrease of said gain by a variable resistor corresponding to said band-pass filter.

Preferably, said gain control means comprises a graphic equalizer.

Preferably, said audio signal recording means includes a first amplifier for amplifying the audio signal output from said gain control means by a predetermined amplification factor in order to control the signal in accordance with frequency characteristics determined by said gain control means, and an oscillator for outputting an oscillation frequency in order to modulate or bias the signal output from said first amplifier and output the modulated or biased signal to an audio recording head.

Preferably, said recording/reproducing system further includes at least one amplifier for amplifying an audio signal by a predetermined amplification factor, between the input of each audio signal and said selecting means, in order to stabilize the input level of said plurality of audio signals.

k Preferably, said recording/reproducing system further includes a means for limiting current, located between said one amplifier and said selecting means.

Preferably, said system further comprises a transmission line for monitoring the output from said gain control means via a monitor means.

According to another aspect of the present invention, there is provided an audio recording apparatus having means for selectively adjusting the gain of an input signal in a plurality of predetermined frequency bands, and means for recording the gain-adjusted signal on a recording medium.

Such an apparatus may further comprise any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

Figure 1 is a circuit diagram of one example of an audio recording apparatus according to the present invention.

Figure 1 is a circuit diagram of an embodiment of an audio recording apparatus applied to a VCR or a video camera or an audio set. Particularly shown are supplied audio signals for recording wherein the reference letter A is a signal output from a tuner of such external equipment as another audio reproducing apparatus, and B is a signal output from a microphone.

In Figure 1, the present embodiment includes a first amplifier 3 for connecting the input of signal A to its non-inverting input and performing linear amplification of the signal, and a second amplifier 6 for connecting the input of signal B to its non-inverting input and performing linear amplification of the signal. Voltage-dividing resistors 1 and 2 are coupled between the input of signal A and the non-inverting input of first amplifier 3, and voltagedividing resistors 4 and 5 are coupled between the output and the inverting input of first amplifier 3 for determining its amplification factor. Voltagedividing resistors 7 and 8 are coupled between the output and the inverting input of a second amplifier 6 for determining its amplification factor.

In a switch 11, the output of first amplifier 3 is connected to a first contact S l, the output of second amplifier 6 to a second contact S2, and the input of a graphic equalizer 12 to a fixed contact SO. A first current-limiting resistor 9 is connected between the output of first amplifier 3 and first contact S l of switch 11, and a second current limiting resistor 10 is connected to the output of a second amplifier 6 and second contact S2 of switch 11.

A plurality of variable resistors 13, 14, 15 and 16 are assigned to respective frequency bands and are capable of being covered in graphic equalizer 12. A third amplifier 18 has its non-inverting input connected to the output of graphic equalizer 12, and a plurality of resistors 20, 22 and 24 and a plurality of capacitors 19 and 23 and a coil 21 are coupled between the inverting input and the output of third amplifier 18 for controlling its gain.

A third current-limiting resistor 26 is coupled between the output of third amplifier 18 and an audio recording head 27, and an oscillator 25 is connected to the node between third current-limiting resistor 26 and audio recording head 27. Here, graphic equalizer 12 is connected to monitor means 17 for monitoring the output signal. Monitor means 17 comprises a speaker (not shown), and an impedance matching means (not shown) placed between the speaker and graphic equalizer 12.

Now the operation of the apparatus shown in Figure 1 will be explained in detail.

First of all, as stated above, the supplied signal A is an audio signal output from external equipment and the supplied signal B is a signal output from a microphone. Here, if the audio system supplying an audio signal into the signal A input is a double-deck system, this audio signal can be from a reproducing deck. Signal A is applied to the non-inverting input of first amplifier 3 via resistors 1 and 2. The applied signal A is amplified by the amplification factor determined by voltage-dividing resistors 4 and 5 coupled between its output and inverting input, and then output.

Meanwhile, signal B is applied to the non-inverting input of second amplifier 6, amplified by the amplification factor determined by voltagedividing resistors 7 and 8 connected between the output and the non-inverting input of second amplifier 6, and then output. The levels of the input signals are controlled by first and second amplifiers 3 and 6 because the input signal levels differ and a constant gain is necessary. The possibility that an audio signal supplied through a microphone is more unstable than the signal supplied from an external equipment is high, so that the level of an input signal can be stabilised by adding another amplifier on the transmission line processing signal B. The input audio signals, whose levels are controlled in first and second amplifiers 3 and 6, are input to switch 11 via first and second current- limiting resistors 9 and 10, respectively.

Switch 11 is a means for selecting the desired audio signal among the signals output from first or second amplifiers 3 and 6, and its switching is controlled by a system controller (not shown in the drawing) controlling the system's overall function, or an exterior switch (not shown in the drawing) fixed to the outside of the system. The audio signal output via switch 11 is provided to graphic equalizer 12.

Graphic equalizer 12 incorporates a plurality of band-pass filters each filtering a respective predetermined frequency band in order to cover high, middle and low audio frequencies. The input audio signal is supplied to each band-pass filter, which filters the signal, and controls the gain according to frequency bands Fl, F2, F3 and F4 by variable resistors 13, 14, 15 and 16 corresponding to each band-pass filter. Therefore, users can selectively set high, middle and low audio frequencies by controlling variable resistors 13 16, then record using the selective settings.

The audio signal which has been controlled by graphic equalizer 12 according to a user's wishes and then output, is supplied to the noninverting terminal of third amplifier 18, and is monitored by monitor means 17 connected to another output of graphic equalizer 12. To control the level of its input audio signal in accordance with frequency characteristics during reproducing, third amplifier 18 determines the amplification factor by capacitors 19 and 23, resistors 20, 22 and 24 and a coil 21.

-7 When the output signal from third amplifier 18 is supplied to audio recording head 27 via third current-limiting resistor 26, the signal having passed through third current-limiting resistor 26 is frequencymodulated or biased by an oscillating frequency output from oscillator 25 and is output.

Audio recording head 27 then records the supplied audio signal onto a recording medium (not shown in the drawing).

is The audio input lines presented in the illustrated embodiment number only two, but it is possible to extend the number of transmission lines with respective amplifiers to provide for a greater plurality of input signals and, accordingly, increase the number of selecting terminals of switch 11 to provide one for each transmission line in order to select the desired signal among the supplied audio signals. Also, graphic equalizer 12 can be configured to cover more than the presented four frequency bands.

The above-described embodiments of the present invention provides an audio recording apparatus capable of recording an audio signal which conforms to a user's desired listening taste, and subsequently reproducing it without any special operation, by using a graphic equalizer during recording 20 of the audio signal.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually 5 exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

1

Claims

1. An audio recording apparatus in a recording/reproducing system for recording and reproducing a video and an audio signal, the apparatus comprising:

selecting means for selecting at least one signal from a plurality of audio signals input during recording; gain control means for increasing or decreasing the gain of an audio signal selected in said selecting means according to predetermined frequency bands; and audio signal recording means for recording on a recording medium an 15 audio signal regulated in said gain control means.

2. An audio recording apparatus as claimed in claim 1, wherein said gain control means includes at least one band-pass filter separated according to said predetermined frequency bands.

3. An audio recording apparatus as claimed in claim 2, wherein said gain control means controls the increase or decrease of said gain by a variable resistor corresponding to said band-pass filter.

4. An audio recording apparatus as claimed in claim 3, wherein said gain control means comprises a graphic equalizer.

5. An audio recording apparatus as claimed in any of the preceding claims, wherein said audio signal recording means includes a first amplifier for amplifying the audio signal output from said gain control means by a predetermined amplification factor in order to control the signal in accordance with frequency characteristics determined by said gain control means, and an oscillator for outputting an oscillation frequency in order to modulate or bias the signal output from said first amplifier and output the modulated or biased signal to an audio recording head.

6. An audio recording apparatus as claimed in any of the preceding claims, wherein said recording/reproducing system further includes at least one amplifier for amplifying an audio signal by a predetermined amplification factor, between the input of each audio signal and said selecting means, in order to stabilize the input level of said plurality of audio signals.

7. An audio recording apparatus as claimed in claim 6, wherein said recording/reproducing system further includes a means for limiting current, located between said one amplifier and said selecting means.

8. An audio recording apparatus as claimed in any of the preceding claims, wherein said system further comprises a transmission line for monitoring the output from said gain control means via a monitor means.

9. An audio recording apparatus substantially as hereinbefore described 25 with reference to the accompanying drawings.

- 11

10. An audio recording apparatus having means for selectively adjusting the gain of an input signal in a plurality of predetermined frequency bands, and means for recording the gain-adjusted signal on a recording medium.

11. An audio recording apparatus according to claim 10, further comprising any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.