초록 ▼

A magnetic head reader circuit comprises a gain stage that is configured to effect multiple functions. In a preferred embodiment, the gain stage is a single stage circuit that includes programmable gain, programmable bandwidth and high-frequency boost, and squelch control. The single stage circuit a

A magnetic head reader circuit comprises a gain stage that is configured to effect multiple functions. In a preferred embodiment, the gain stage is a single stage circuit that includes programmable gain, programmable bandwidth and high-frequency boost, and squelch control. The single stage circuit also includes a folded cascode current drive that provides an increased dynamic range of the gain stage. To provide a low DC offset, the reader also includes an integrator that is operated in closed loop to appropriately attenuate the currents from the cascode current drive. By employing a multi-function single stage reader, a substantial reduction in circuit area, and a substantial increase in bandwidth, is achieved.

대표청구항 ▼

A magnetic head reader circuit comprises a gain stage that is configured to effect multiple functions. In a preferred embodiment, the gain stage is a single stage circuit that includes programmable gain, programmable bandwidth and high-frequency boost, and squelch control. The single stage circuit a

A magnetic head reader circuit comprises a gain stage that is configured to effect multiple functions. In a preferred embodiment, the gain stage is a single stage circuit that includes programmable gain, programmable bandwidth and high-frequency boost, and squelch control. The single stage circuit also includes a folded cascode current drive that provides an increased dynamic range of the gain stage. To provide a low DC offset, the reader also includes an integrator that is operated in closed loop to appropriately attenuate the currents from the cascode current drive. By employing a multi-function single stage reader, a substantial reduction in circuit area, and a substantial increase in bandwidth, is achieved. entire periphery. 2. An optical element according to claim 1, wherein a part of said projecting portion is buried in said outer peripheral edge surface of said lens optical surface. 3. An optical element production method comprising the steps of: forming an projecting portion adjacent to an opening of an inner wall portion of a lens holder; inserting a lens material in said lens holder; press-fitting said lens material into said lens holder by heating, pressing and deforming by a die, thereby forming a lens optical surface of an optical lens at said opening in the direction of the optical axis of said optical lens; and deforming said projecting portion by said die so that a part of said projecting portion is buried in an outer peripheral edge surface of said lens optical surface. 4. An optical element production method comprising the steps of: inserting a lens material in a lens holder having an inner wall portion; press-fitting said lens material into said lens holder by heating, and pressing and deforming by a die, thereby forming a lens optical surface of an optical lens at an opening in the lens holder in the direction of the optical axis of said optical lens; extending a die surface for pressing a pressed surface of said lens material outside said inner wall portion of said lens holder at said step of press-fitting said lens material; and performing molding while an outer peripheral edge surface of said lens optical surface and an outer flat surface of said lens holder are covered with said die surface. 5. An optical element according to claim 1 further including a groove formed on said inner wall portion of said lens holder, wherein a part of said optical lens fills said groove thereby reliably holding said optical lens in said lens holder. 6. An optical element according to claim 1, wherein said lens holder is made of metal and shaped like a hollow cylinder. 7. An optical element production method according to claim 3 further including the steps of: forming a groove in said inner wall portion of said lens holder; filling said groove with said lens material at said step of press-fitting. 8. An optical element production method according to claim 3, wherein said projecting portion is annularly shaped, and; wherein said lens material is optical glass.