GB1580960A - Coding devices for channel selection in radio communication apparatuses - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO CODING DEVICES FOR CHANNEL SELECTION IN RADIO COMMUNICATION APPARATUSES ~ (71) I, OLE SIMON PETERSEN, of Peder Paarsvej 12, DK-9000 Aalborg, Denmark, a Danish subject, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to coding devices for selecting channels in radio communication apparatuses in which a desired frequency is synthesized by the use of a programmable frequency divider.

In US Patent Application Serial No.

736,246 (Serial No. 1 533 056) (British Patent Application No. 46119/76), a coding member is described for use in the programming of a frequency synthesizer for radio communication use. The coding member in the application mentioned may be programmed in different stages; either at the time of its manufacture by pressing-up protusions or when servicing the apparatus by inserting screws in threaded holes.

Furthermore there are certain positions that cannot be influenced.

Moreover, if a ve large number of positions and hence of contacts this coding member is desired, the coding member of US Patent Application Serial No. 736,246 is impractical at the manufacturing stage as well as when performing changes in the coding in the field.

According to the invention, there is provided a coding device for selecting a communication channel in a radio communication apparatus, comprising a coding member in the form of a rotatable subsequentially cylindrically shaped carrying body, an idexing mechanism connected to and arranged to selectively secure the carrying body in a number of predetermined positions, each of which corresponds to a communication channel, and an array of equidistantly disposed contact fingers for cooperation with combs of the carrying body, the carrying body having longitudinal radial groove means provided at equidistant circumferential spacing around the outer portion of the carrying body, the combs being removably inserted in the respective groove means, the number of combs corresponding to the number of predetermined positions of the coding member and to the number of communication channels, each comb having one or more projections constituting teeth arranged to cooperate with and make contact with associated contact fingers, the individual longitudinal positions of the teeth on each comb on the carrying body defining by predetermined engagement with associated contact fingers a binary representation of the frequency of the selected channel, each comb and the carry in body being made from an electrically conductive material and being assembled in electrically conductive engagement; so that the carrying body constitutes a common electrical terminal.

A preferred coding device permits the selection of a very large number of channels in a manner which is suitable for series production and which is changeable with simple means.

The presence or non-presence of a particular tooth determines whether the corresponding contact finger is to make contact with the comb or not. Since the coding is binary, the presence or non-presence determines whether there is to be a "one" or a "zero" on a line connecting the particular contact finger to the coder for the frequency synthesizer.

By placing the combs in axial grooves in a cylindrical carrying body, a well-defined interval between successive combs is obtained.

Preferably, the ends of each of the combs are provided with extensions of unequal lengths, the carrying body comprising an axle, two outer discs each having circumferentially and equidistantly arranged oblong holes for receiving the extensions, and at least one intermediate or inner disc having circumferentially and equidistantly arranged radial slits for supporting the combs, all of the discs being secured to the axle and the discs being evenly spaced along the axle, the oblong holes and the radial slits being in aligned registry with each other parallel to the axle. Such coding member is well suited to series production and provides a saving in materials.

A preferred coding member may be programmed by cutting the teeth of the combs in accordance with the particular binary representation of the frequency to besynthes- ized when a particular comb is engaged by the contact fingers. The cutting may take place at the manufacturing stage using a tool to make the combs from metal strips or it may take place in the field by means of a special cutter that is moved from position to position along a comb with preformed but uncut teeth. A large degree of versatility is obtained in this manner as reprogramming in the field may be performed by simple substitution of new, factory-programmed combs for old or by tooth-by-tooth cutting as described above.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, in perspective sketch form, a preferred coding member interacting with a set of contact fingers; Figure 2 shows a longitudinal section in the direction A-A of Figure 1; Figures 3a and b show cross sections in the direction B-B and C-C, respectively, of Figure 2; Figure 4 shows a longitudinal section through a coding member consisting of combs in a degenerated, "skeleton" carrying body; and Figures 5a and b show the disposition of slits in a carrying disc.

Figure 1 gives an impression of the general arrangement of coding member 1, 2 and contact fingers 3. An indexing mechanism I ensures that the comb 2 will only be in proper engagement at a predetermined point of rotation. The sliding movement of the comb with respect to the contact fingers 3 provides a self-cleaning action. The carrying body 1 and combs 2 are conductive and connected to ground so that coding of a frequency divider D takes place through grounding those inputs which are selected by the teeth of the comb 2 in engagement with the contact fingers 3.

Figure 2 is self-explanatory and shows the manner in which certain of the contact fingers 3 engage the comb 2.

Figure 3a shows in detail the engagement of a contact finger 3 ' and a tooth 2'.

Figure 3b shows in detail the failing of a contact finger 3" to make contact with a cut tooth 2", the contact finger 3" thus resting against an insulating stud 4.

Figure 4 shows the carrying body composed of inner discs 5, outer discs 7, and bushing 6 fixed to an axle. It is shown that inward radial movement of the comb 2 is restricted by discs 5 as well as by discs 7 while outward radial movement is restricted by discs 7 only. Removal of a comb from the carrying body is effected by pushing it to the left, thereby disengaging the shorter end 10 of the comb 2 from the disc 7, allowing the right part of the comb 2 to be moved radially outwardly and the longer other end 11 to be pulled through the oblong hole in disc7'.

Figures 5a and b show the slits 8 and 9, respectively. Manufacture of such discs is relatively simple.

The use of several segments of contact fingers to engage different parts of the combs is equivalent to connecting the carrying bodies in a row on the same axis. The only difference is that the comb is made in one long Piece and, for this reason, this manner of construction is not explicitly shown in the drawings.

WHAT I CLAIM IS: 1. A coding device for selecting a communication channel in a radio communication apparatus, comprising a coding member, in the form of a rotatable substantially cylindrically shaped carrying body, an indexing mechanism connected to and arranged to selectively secure the said carrying body in a number of predetermined positions, each of which corresponds to a communication channel, and an array of equidistantly disposed contact fingers for cooperation with combs of the carrying body, the carrying body having longitudinal radial groove means provided at equidistant circumferential spacing around the outer portion of the carrying body, the combs being removably inserted in the respective groove means, the number of combs corresponding to the number of predetermined positions of the coding member and to the number of communication channels, each comb having one or more projections constituting teeth arranged to cooperate with and make contact with associated contact fingers, the individual longitudinal positions of the teeth on each comb on the carrying body defining by predetermined engagement with associated contact fingers a binary representation of the frequency of the selected channel, each comb and the carrying body being made from an electrically conductive material and being assembled in electrically conductive engagement so that the carrying body constitutes a common electrical termu-

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. axle, two outer discs each having circumferentially and equidistantly arranged oblong holes for receiving the extensions, and at least one intermediate or inner disc having circumferentially and equidistantly arranged radial slits for supporting the combs, all of the discs being secured to the axle and the discs being evenly spaced along the axle, the oblong holes and the radial slits being in aligned registry with each other parallel to the axle. Such coding member is well suited to series production and provides a saving in materials. A preferred coding member may be programmed by cutting the teeth of the combs in accordance with the particular binary representation of the frequency to besynthes- ized when a particular comb is engaged by the contact fingers. The cutting may take place at the manufacturing stage using a tool to make the combs from metal strips or it may take place in the field by means of a special cutter that is moved from position to position along a comb with preformed but uncut teeth. A large degree of versatility is obtained in this manner as reprogramming in the field may be performed by simple substitution of new, factory-programmed combs for old or by tooth-by-tooth cutting as described above. The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, in perspective sketch form, a preferred coding member interacting with a set of contact fingers; Figure 2 shows a longitudinal section in the direction A-A of Figure 1; Figures 3a and b show cross sections in the direction B-B and C-C, respectively, of Figure 2; Figure 4 shows a longitudinal section through a coding member consisting of combs in a degenerated, "skeleton" carrying body; and Figures 5a and b show the disposition of slits in a carrying disc. Figure 1 gives an impression of the general arrangement of coding member 1, 2 and contact fingers 3. An indexing mechanism I ensures that the comb 2 will only be in proper engagement at a predetermined point of rotation. The sliding movement of the comb with respect to the contact fingers 3 provides a self-cleaning action. The carrying body 1 and combs 2 are conductive and connected to ground so that coding of a frequency divider D takes place through grounding those inputs which are selected by the teeth of the comb 2 in engagement with the contact fingers 3. Figure 2 is self-explanatory and shows the manner in which certain of the contact fingers 3 engage the comb 2. Figure 3a shows in detail the engagement of a contact finger 3 ' and a tooth 2'. Figure 3b shows in detail the failing of a contact finger 3" to make contact with a cut tooth 2", the contact finger 3" thus resting against an insulating stud 4. Figure 4 shows the carrying body composed of inner discs 5, outer discs 7, and bushing 6 fixed to an axle. It is shown that inward radial movement of the comb 2 is restricted by discs 5 as well as by discs 7 while outward radial movement is restricted by discs 7 only. Removal of a comb from the carrying body is effected by pushing it to the left, thereby disengaging the shorter end 10 of the comb 2 from the disc 7, allowing the right part of the comb 2 to be moved radially outwardly and the longer other end 11 to be pulled through the oblong hole in disc7'. Figures 5a and b show the slits 8 and 9, respectively. Manufacture of such discs is relatively simple. The use of several segments of contact fingers to engage different parts of the combs is equivalent to connecting the carrying bodies in a row on the same axis. The only difference is that the comb is made in one long Piece and, for this reason, this manner of construction is not explicitly shown in the drawings. WHAT I CLAIM IS:

1. A coding device for selecting a communication channel in a radio communication apparatus, comprising a coding member, in the form of a rotatable substantially cylindrically shaped carrying body, an indexing mechanism connected to and arranged to selectively secure the said carrying body in a number of predetermined positions, each of which corresponds to a communication channel, and an array of equidistantly disposed contact fingers for cooperation with combs of the carrying body, the carrying body having longitudinal radial groove means provided at equidistant circumferential spacing around the outer portion of the carrying body, the combs being removably inserted in the respective groove means, the number of combs corresponding to the number of predetermined positions of the coding member and to the number of communication channels, each comb having one or more projections constituting teeth arranged to cooperate with and make contact with associated contact fingers, the individual longitudinal positions of the teeth on each comb on the carrying body defining by predetermined engagement with associated contact fingers a binary representation of the frequency of the selected channel, each comb and the carrying body being made from an electrically conductive material and being assembled in electrically conductive engagement so that the carrying body constitutes a common electrical termu-

nal.

2. A coding device as claimed in claim 1, in which the ends of each of the combs are provided with extensions of unequal lengths, the carrying body comprising an axle, two outer discs each having circumferentially and equidistantly arranged oblong holes for receiving the extensions, and at least one intermediate or inner disc having circumferentially and equidistantly arranged radial slits for supporting the combs, all of the discs being secured to the axle and the discs being evenly spaced along the axle, the oblong holes and the radial slits being in aligned registry with each other parallel to the axle.

3. A coding device for programming a radio communication apparatus, substantially as hereinbefore described with reference to the accompanying drawings.

4. A method of coding a coding member of a device as claimed in any one of the preceding claims consisting in cutting the teeth of each comb in accordance with the binary representation of the frequency of the channel to be selected by each comb.

5. A radio communication apparatus including a coding device as claimed in any one of claims 1 to 3, the apparatus further including a programmable frequency divider whose programming inputs are connected to the respective contact fingers, the carrying body being connected to earth.