GB2209259A

GB2209259A - A mixed filter circuit

Info

Publication number: GB2209259A
Application number: GB8710646A
Authority: GB
Inventors: Victor John Gordon Gale
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-05-06
Filing date: 1987-05-06
Publication date: 1989-05-04
Also published as: GB8710646D0

Abstract

A mixed filter circuit comprises an LCR band pass filter in combination with a ceramic cut-off filter. The filter may be used in a guitar pickup circuit to produce a desired tone. Alternatively, the filter circuit may be used in noise filtering for record reproduction and it may be adapted for use as an aerial circuit in TV or radio. <IMAGE>

Description

A MIXED FILTER AUDIO CIRCUIT This Invention relates to a Mixed Filter Audio Circuit Mixed Filter Audio Circuits are widely used in Amplification recording, and efficient Electronic equipment. A particular type of equipment in common use which incorporates a Mixed Filter System, the record player, has 'a rumble' and a 'Scratch Filter' circuit in one, or part of one or several units. The Rumble circuit rejects frequencies below a given frequency, low noises ie Motor interference, and High frequencies ie scratches, from used, and old record discs.

The Mixed Filter Audio Circuit will adapt to Guitar noises and even to Input frequencies of an Aerial Circuit of a TV or radio. Relatively cheap to make, prices of components may be expensive in a production Model.

This invention illustrated, has several features required for accurate performance. A low pass coil filter is incorporated into a Band pass filter which regulates a wave-length in a TV and Radio. The signal now cleaner, is passed through a Ceramic Filter of cut off frequency and at DB's Octave. This still provides for a Characteristic Tone, which is left to be further amplified if required, by another unit, two sockets are built into the two opposite sides of the Box construction, incorporated to transfer the signal by way of a Standard Jack and Lead.

Earth is by way of an isolated strip, whereby leads appropriate are connected.

A specific embodiment of the invention will now be described by way of example with reference to three accompanying Drawings, figure 1, figure 2 and figure 3 in which: FIGURE 1 Shows the circuit, in relative perspective to the layout of Components and their values in respective quantities, pertaining to each component Resistors to Ohms, (K) Capacitors u to Micro-forads and the Coil to (uh) micro hennies. Figure 1 also has a key to Circuit Markings and Symbols used. The coil is a 1.2mm copper wire wound to 6.8 turns, and Measured in Hennies. The Band pass filter has a Gain of 5 as a separate circuit and the power Sources are from a 9 volt P.P.3. Battery. The Circuit is designed to operate on a negative to positive Voltage working Basis, earth separate.The Matrix .15 is used to connect the Components to, Moreover soldered onto Copper Strips. Explained further in figure 2. L.C.R. refers to a marking on the Component if desired several values may be used between .15uf and .33uf. The values given are only a guide line, the layout only is specific.

FIGURE 2 This layout illustrates the exploded view and accurate placings of the Components. Connecting wires are used to connect to earth and from one Matrix Strip to the other. An Earth Strip is provided for common usage, and connects the Sockets and the Earth tag from the Ceramic filter. A Key is used to explain the parts from A to R.

.1J Matrix again, is only a Guide line other Vereo board Sizes are avilable and can be used to ones desirable, or necessary needs. ie the larger the Box, the larger the unit, and Components used. A Battery Connector or lead R is used on points + G and -L respectively.

FIGURE 3 This diagram illustrates a Box, of wooden, Metal or Plastic Construction. Ample space has been provided for, to clear Sockets B and C from the Vereo board and sides of front of Box. Chocks of wood, or mounts E and J are used to screw the Vereo board down to a position flush with rear of the box D. A Battery Box is also incorporated to keep the power Module straight and tightly secure to avoid damage and present neatness. Invented Prototype is a Cigarette Box.

To Employ the usage of the filter circuit, a battery P.P.3. 9 Volts must first be inserted. The leads with Standard Jacks can then be inserted, to connect to the Amplifier from a source of origin ie Guitar, record deck, Aerial Coax Jack, Organ or Drum Synthesiser. Jacks.

REFERENCE KEY TO DRAWINGS Key to Figure 1 Key to Figure 3 i/p Input A. .15 Matrix o/p Output B & C. Sockets Earth to Earth Strip D. Box with Hinged Lid E. Battery Box 3 sides Wood or Plastic F. & G. Screws H & J. Wood chocks to support Matrix Key to Figure 2 A. Earth strip B. Lead to SKT. A C. 47K resistor D. 6 Turn Coil. 2mm. Copper E. 2uf Capacitor F. 100K resistor G. Positive Terminal H. LCR Component .15 - .33uf J. Connecting Wire K. 100K resistor L. Negative Terminal M. Ceramic filter N. Connecting Wire to O. Connecting Lead P. Lead to B. SKT R. Battery Clip

Claims

CLAThS 1. A Mixed Filter Audio Circuit, comprising of a low frequency L.C.R.

Circuit, one Band pass circuit incorporated therein, with.a Ceramic filter. The low frequency filter circuit has a 1.2mm thick copper coil to pass frequencies and ensure a good Mellow Tone. The Box in which the Circuit is fixed has two sockets, one Input and one Output, of a stereo type: interchanges of Stereo to Mono can be made as indeed Amendments with a 2pf variable capacitor in series with the L.C.R. Component .15-.33uf.
2. A Mixed Filter Audio Circuit, as claimed in claim 1, with a copper coil of Mains wire Grade, to ensure a good, constant Tone, passing Lower frequencies on the Treble Band.
3. A Mixed Filter Audio Circuit as claimed in claims 1 and 2, wherein the L.C.R. Circuit is incorporated in the Band pass filter circuit to ensure a Band pass set of frequencies, controlled by a particular range of frequencies within the choice of values of components and their limits.
4. A Mixed Filter Audio Circuit as claimed in claims t and 2 and 3, wherein a Ceramic Filter is connected to the Junction of the 100K resistor R3 and the L.C.R. Component .33uf, .15-33uf. To ensure Frequencies already passed, only pass into the Ceramic filter and are regulated to pass only a portion of that signal to the output across the resistor R3 at the Junction of the positive terminal + 9 volts and the Resistor R3.
5. A Mixed Filter Audio Circuit as described and claim in preceding 4 Claims with an addition of a 2pl capacitor, connected in parallel with C1 and in series with C2 to the Junction of R3, the Ceramic Filter and the L.C.R. Components C2, .15uf-.33uf as C3.
6. A Mixed Filter Audio Circuit as described and claimed in 1,2,3,4,5.

with an Earthing Strip in Figure 2, as a. This Strip ensures a common earth to the Input, Output and Ceramic Filter to the Earth of the connecting equipment.
7. A Mixed Filter Audio Circuit substantially as described herein with a lid and catch to a box, to contain the circuit on Veroboard.
8. A Mixed Filter Audio Circuit, with illustrated Drawings figure 1, 2 and 3 as a reference for construction.