Patent EP0107295A2 successfully refreshed from Google Patents.
EP0107295A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Video disc type recording and reproducing system
Assignee: Pioneer Corp
•
Filing: 1983-08-30
•
Granted: —
•
Expires: 2003-08-30
Abstract
Abstract A video disc recording/reproducing system is improved by preventing secondary or higher order sidebands of the FM modulated video signal from affecting an audio signal multiplexed with the video signal. This is achieved by incorporating a filter means 8a which is connected between a first frequency modulator 1 for modulating a video signal and an adder circuit 3 in which the modulated video signal is combined with a modulated audio signal from the audio modulator 2. The output from the adder circuit 3 is fed via a limiter 4 to an electrical/optical modulator 5.
Inventors
- 👤 Ryoji Nansei Heights Sakamoto 203 Higashi
- 👤 Satoru Nomura
- 👤 Kazuo Pioneer Electronic Corporation Kuroda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 19:41
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10527; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/92; H04N5/9201; H04N5/9202; H04N5/9204
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
22 words
A video disc type recording and reproducing system, comprising recording means and reproducing means, the recording means comprising a first frequency modulator
Claim 2
Dependent Claim
22 words
A video disc type recording and reproducing system, comprising recording means and reproducing means, the recording means comprising a first frequency modulator
Claim 3
Dependent Claim
128 words
(1), for modulating a video signal, a second frequency modulator (2) for modulating an audio signal,an adder circuit (3) for adding the modulated video and audio signals, a limiter (4) connected to an output of the adder circuit (3) for pulse width modulating the output signal from the adder circuit (3), and an electrical/optical modulator (5) connected to the limiter (4) characterised by filter means (8a) connected between an output of the first frequency modulator (1) and the adder circuit (3) for removing a frequency component of the frequency-modulated video signal which covers a frequency component of the frequency modulated audio signal from the second frequency modulator (2) to prevent second and higher order sidebands of the modulated video signal interfering with the audio signal multiplexed with it.
Claim 4
Dependent Claim
128 words
(1), for modulating a video signal, a second frequency modulator (2) for modulating an audio signal,an adder circuit (3) for adding the modulated video and audio signals, a limiter (4) connected to an output of the adder circuit (3) for pulse width modulating the output signal from the adder circuit (3), and an electrical/optical modulator (5) connected to the limiter (4) characterised by filter means (8a) connected between an output of the first frequency modulator (1) and the adder circuit (3) for removing a frequency component of the frequency-modulated video signal which covers a frequency component of the frequency modulated audio signal from the second frequency modulator (2) to prevent second and higher order sidebands of the modulated video signal interfering with the audio signal multiplexed with it.
Claim 5
Dependent Claim
30 words
A system according to claim 1, wherein the filter means (8a, Figure 3) comprises a band eliminating filter for removing only a lower secondary sideband of the frequence-modulated video signal.
Claim 6
Dependent Claim
35 words
A system according to claim 1, wherein the filter means comprises a high pass filter (8a, Figure 7) for passing components having a frequency higher than the lower secondary sideband of the modulated video signal.
Claim 7
Dependent Claim
59 words
A system according to claim 2, wherein the recording means further comprises a compensating circuit (9a, Figure 5) connected between the band eliminating filter (8a) and the adder circuit (3), the compensating circuit having a substantially constant gain and a group delay characteristic so that it substantially cancels out the group delay characteristic of the band eliminating filter (8a).
Claim 8
Independent Claim
29 words
A system according to any one of the preceding claims, wherein the recording means further comprises a digital encoder (10) connected in parallel with the second frequency modulator (2).
Claim 9
Independent Claim
40 words
A system according to any one of the preceding claims, further including a third frequency modulator (2a, 3a) for modulating a second audio signal, an output of the third frequency modulator (2a, 3a) being supplied to the adder circuit (3).
Claim 10
Dependent Claim
51 words
A system according to claim 6, when dependent upon claim 5, wherein the digital encoder (10) receives the first and second audio signals and digitises them in a time sharing manner, outputs of the digital encoder (10) and of the third frequency modulator (3a) being supplied to the adder circuit (3).
Claim 11
Independent Claim
54 words
A system according to any one of the preceding claims,wherein the reproducing means includes an information pick-up (8, 11), an amplifier (9, 12) coupled to the pick-up, and at least a video band pass filter (13) and an audio low pass filter (14) coupled in parallel to the output of the amplifier (9, 12).
Claim 12
Dependent Claim
48 words
A system according to claim 8, wherein an output(A) of the video band pass filter (13) is coupled to video detector means (16), and an output (B) of the audio low pass filter (14) is coupled to audio detector means (18) via audio band pass filter means (17).
Claim 13
Dependent Claim
67 words
A system according to claim 9, wherein the recording means includes a digital encoder (10) connected in parallel with the second frequency modulator (2) and receives an audio input, and wherein the reproducing means includes a series low pass filter (15) passing digitised audio components of the signal output by the amplifier (9), and a decoder (19) receiving an output of the series low pass filter (15).
Claim 14
Dependent Claim
27 words
A system according to claim 10, further including switching means (20,21) for selecting an output of either the audio detector means (18) or of the decoder (19).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.