Skip to content Skip to navigation

OpenStax_CNX

You are here: Home » Content » cid_DetectStartBit.vi

Navigation

Lenses

What is a lens?

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

This content is ...

In these lenses

  • LabVIEW Digital Communications display tagshide tags

    This module is included inLens: Analog / Digital Communications with National Instruments LabVIEW
    By: Sam ShearmanAs a part of collections: "SubVI Specifications for "Communication Systems Projects with LabVIEW"", "Communication Systems Projects with LabVIEW"

    Comments:

    ""Communication Systems Projects with LabVIEW" features ten projects that draw upon a library of over 40 subVIs constructed as part of the project activities. Each module in this manual completely […]"

    "Starting point collection that gathers all modules from this course"

    Click the "LabVIEW Digital Communications" link to see all content selected in this lens.

    Click the tag icon tag icon to display tags associated with this content.

Recently Viewed

This feature requires Javascript to be enabled.

Tags

(What is a tag?)

These tags come from the endorsement, affiliation, and other lenses that include this content.
 

cid_DetectStartBit.vi

Module by: Ed Doering. E-mail the authorEdited By: Erik Luther, Sam Shearman, Brett Hern

Summary: Build a LabVIEW subVI to detect the first start bit in the Caller ID message bitstream.

Table 1
LabVIEWtop.png This module refers to LabVIEW, a software development environment that features a graphical programming language. Please see the LabVIEW QuickStart Guide module for tutorials and documentation that will help you:
• Apply LabVIEW to Audio Signal Processing
• Get started with LabVIEW
• Obtain a fully-functional evaluation edition of LabVIEW

Note:

Visit LabVIEW Setup to learn how to adjust your own LabVIEW environment to match the settings used by the LabVIEW screencast video(s) in this module. Click the "Fullscreen" button at the lower right corner of the video player if the video does not fit properly within your browser window.

LabVIEW SubVI: cid_DetectStartBit.vi

  • Description: Detect the first start bit in the Caller ID message bitstream, and return only the remaining bits in the bitstream. The Caller ID message consists of three distinct regions: (1) channel seizure (alternating pattern of T and F values), (2) steady mark (constant T values), and (3) data block containing the message payload. This subVI detects the steady mark region and then identifies the array index (time point) at which the input bitstream first changes to F.
  • Category: Caller ID decoding ("cid" prefix)

Inputs (Controls)

  1. bitstream in -- 1-D Boolean array

Parentheses ( ) indicate default value; square brackets [ ] designate units.

Outputs (Indicators)

  1. datablock bitstream -- 1-D Boolean array
  2. start bit index -- I32

Required Behavior

  • The bitstream in input should contain a complete Caller ID message bitstream as generated by other demodulating and bit synchronization and sampling subsystems.
  • The datablock bitstream output contains only the data block portion of the input bitstream, beginning with the first start bit of the first character, i.e., the first frame. If no data block is detected then datablock bitstream will return empty.
  • start bit index is the index (location) of the data block detected in the input message. If no data block is detected then start bit index will return -1.

LabVIEW Coding Tips

View the screencast video in Create a SubVI in LabVIEW to learn the mechanics of subVIs.

Refer to the Figure 1 screencast video for LabVIEW coding tips and techniques specific to this subVI.

Figure 1: [video] LabVIEW coding tips and techniques for cid_DetectStartBit.vi
Figure 1 (subVI_cid_DetectStartBit-vi.htm)

Content actions

Download module as:

PDF | EPUB (?)

What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

Downloading to a reading device

For detailed instructions on how to download this content's EPUB to your specific device, click the "(?)" link.

| More downloads ...

Add module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks