User`s manual

18
3. Editing Delay Parameters
Delay times are generated in the ISP-100 by using system memory and NOT
DSP cycles. This is a great advantage over some other products by not wasting
DSP resources for this function. Therefore, when you change delay parameters,
you will not see any impact on DSP resources.
Each DSP chip is capable of a maximum of 2.7 seconds (2700 Ms), for a total
system allocation of 8.1 seconds (8100 Ms). The QuickBUILD

software will
monitor your delay usage per chip and not allow you to exceed this limit. For
example, if you place a 2500 Ms delay in a given chip, the next delay device you
place (in that same chip) will only be allowed up to 200 Ms.
If you did not assign a delay time when you placed your Delay device, or you
want to change that time, right mouse click and select “Edit”. You will see the
following dialog window:
Figure 19.
You can either type in the delay value you want in the Max Delay Time window,
or you can use the “Up and Down” arrows. The arrows will change the delay time
in 50 Ms increments.
In order to explain the Delay Bias, you need to understand some basic
characteristics of analog and digital inputs and outputs. When you are bringing in
an analog audio signal to a digital processor, or sending out a digital signal to the
analog world, that signal must go through an Analog to Digital (A to D) or Digital
to Analog (D to A) converter. The process of converting this signal requires a
certain amount of time, usually under 2 Ms. If all of your inputs and/or outputs are
going through these converters, they will be effected by this time factor evenly.
Therefore the signals will be “time aligned” correctly. If you are co-mingling
analog signals with digital signals within the same system, there will be a delay
discrepancy between these signals, since no time delay is occurring with the
digital signal. In order to have correct time alignment with all of your audio
signals, the digital signal will need to be “artificially delayed” to align with the
analog signal. The Delay Bias is typically used to correct these delay offsets.
Manual adjustment of this parameter will be discussed in the Advanced Design
section of this manual.